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Phylogenetic analyses of 131 terminals of Paspalum and related genera, based on both plastid and nuclear markers, were performed under maximum parsimony and Bayesian methods. The total evidence analyses generated a hypothesis showing that Paspalum would be monophyletic if Spheneria, Thrasyopsis and Reimarochloa are included within the genus. Paspalum inaequivalve and P. microstachyum, two species of the Inaequivalvia group were related to genus Anthaenantiopsis, excluded from Paspalum, or nested within it by plastid and nuclear markers, respectively. Subgenera Anachyris and Harpostachys were partially recovered as monophyletic assemblages, while subg. Ceresia and Paspalum resolved as polyphyletic. Within subgenus Paspalum, some informal groups were recovered as monophyletic, while others were resolved as paraphyletic or polyphyletic. Phylogenetic relationships among species of Paspalum were partially recovered possibly due to reticulation events among species, autopolyploidization and apomixis; all these processes being common in Paspalum, thus obscuring the infrageneric classification. Fil: Scataglini, María Amalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Giussani, Liliana Mónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Denham, Silvia Suyai. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Morrone, Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

Taxonomic features of species of Panicum section Parviglumia are reviewed and compared with those of other taxa in tribe Paniceae. The new genus Morronea, including six species ranging from Mexico to Argentina, is proposed on the basis of morphological and molecular characters. They are plants growing at forest edges, with membranous-ciliate ligules, lower glume reduced, 1/6 to 1/4 the spikelet length, lower palea and lower flower absent, and upper anthecium indurate with simple papillae and conspicuous macrohairs all over its surface. The new combinations: Morronea arundinariae, M. cayoensis, M. guatemalensis, M. incumbens, M. parviglumis , and M. trichidiachnis are proposed and the new genus is compared with other genera of the tribe Paniceae.

Dated molecular phylogenetic trees show that the Andean uplift had a major impact on South American biodiversity. For many Andean groups, accelerated diversification (radiation) has been documented. However, not all Andean lineages appear to have diversified following the model of rapid radiation, particularly in the central and southern Andes. Here, we investigated the diversification patterns for the largest South American-endemic lineage of Brassicaceae, composed of tribes Cremolobeae, Eudemeae and Schizopetaleae (CES clade). Species of this group inhabit nearly all Andean biomes and adjacent areas including the Atacama–Sechura desert, the Chilean Matorral and the Patagonian Steppe. First, we studied diversification times and historical biogeography of the CES clade. Second, we analysed diversification rates through time, lineages and associated life forms. Results demonstrate that early diversification of the CES clade occurred in the early to mid-Miocene (c. 12–19 Mya) and involved the central Andes, the southern Andes and the Patagonian Steppe, and the Atacama–Sechura desert. The Chilean Matorral and northern Andes were colonized subsequently in the early Pliocene (4–5 Mya). Diversification of the CES clade was recovered as a gradual process without any evidence for rate shifts or rapid radiation, in contrast to many other Andean groups analysed so far. Diversification time/rates and biogeographical patterns obtained for the CES clade are discussed and compared with patterns and conclusions reported for other Andean plant lineages. Fil: Salariato, Diego Leonel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Franzke, Andreas. Heidelberg University; Alemania Fil: Mummenhoff, Klaus. University of Osnabrück; Alemania Fil: Al-Shehbaz, Ihsan. Missouri Botanical Garden; Estados Unidos

En esta contribución se intenta clarificar el nombre actual de una especie de Astragalus de Chile, inicialmente descripta como A. trifoliatus por Philippi y luego considerada por Spegazzini bajo A. valparidisiensis. Se concluye que el último nombre es superfluo, por lo que el nombre actual para esta especie endémica, y de distribución restringida, debe ser A. trifoliatus. This contribution intends to clarify the current name of a species of Astragalus from Chile, originally described as A. trifoliatus by Philippi and later considered by Spegazzini as A. valparadisiensis. We concluded that the latter name is a superfluous one, and that the current name of this endemic and restricted species should be A. trifoliatus. Fil: Teillier, S.. Universidad de Chile; Chile Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

Background: Panicoideae are the second largest subfamily in Poaceae (grass family), with 212 genera and approximately 3316 species. Previous studies have begun to reveal relationships within the subfamily, but largely lack resolution and/or robust support for certain tribal and subtribal groups. This study aims to resolve these relationships, as well as characterize a putative mitochondrial insert in one linage. Results: 35 newly sequenced Panicoideae plastomes were combined in a phylogenomic study with 37 other species: 15 Panicoideae and 22 from outgroups. A robust Panicoideae topology largely congruent with previous studies was obtained, but with some incongruences with previously reported subtribal relationships. A mitochondrial DNA (mtDNA) to plastid DNA (ptDNA) transfer was discovered in the Paspalum lineage. Conclusions: The phylogenomic analysis returned a topology that largely supports previous studies. Five previously recognized subtribes appear on the topology to be non-monophyletic. Additionally, evidence for mtDNA to ptDNA transfer was identified in both Paspalum fimbriatum and P. dilatatum, and suggests a single rare event that took place in a common progenitor. Finally, the framework from this study can guide larger whole plastome sampling to discern the relationships in Cyperochloeae, Steyermarkochloeae, Gynerieae, and other incertae sedis taxa that are weakly supported or unresolved. Fil: Burke, Sean V.. Northern Illinois University; Estados Unidos Fil: Wysocki, William P.. Northern Illinois University; Estados Unidos Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Craine, Joseph M.. Jonah Ventures; Estados Unidos Fil: Pires, J. Chris. University of Missouri; Estados Unidos Fil: Edger, Patrick P.. Michigan State University; Estados Unidos Fil: Mayfield Jones, Dustin. Donald Danforth Plant Science Center; Estados Unidos Fil: Clark, Lynn G.. Iowa State University; Estados Unidos Fil: Kelchner, Scot A.. University of Idaho; Estados Unidos Fil: Duvall, Melvin R.. Northern Illinois University; Estados Unidos

Fil: Arias, Salvador. Universidad Nacional Autónoma de México; México Fil: Berendsohn, Walter G.. Freie Universität Berlin; Alemania Fil: Borsch, Thomas. Freie Universität Berlin; Alemania Fil: Flores Olvera, Hilda. Universidad Nacional Autónoma de México; México Fil: Ochoterena, Helga. Universidad Nacional Autónoma de México; México Fil: von Mering, Sabine. Freie Universität Berlin; Alemania Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

Grasses are ancestrally tropical understory species whose current dominance in warm open habitats is linked to the evolution of C4 photosynthesis. C4 grasses maintain high rates of photosynthesis in warm and water stressed environments, and the syndrome is considered to induce niche shifts into these habitats while adaptation to cold ones may be compromised. Global biogeographic analyses of C4 grasses have, however, concentrated on diversity patterns, while paying little attention to distributional limits. Using phylogenetic contrast analyses, we compared macro-climatic distribution limits among ~1300 grasses from the subfamily Panicoideae, which includes 4/5 of the known photosynthetic transitions in grasses. We explored whether evolution of C4 photosynthesis correlates with niche expansions, niche changes, or stasis at subfamily level and within the two tribes Paniceae and Paspaleae. We compared the climatic extremes of growing season temperatures, aridity, and mean temperatures of the coldest months. We found support for all the known biogeographic distribution patterns of C4 species, these patterns were, however, formed both by niche expansion and niche changes. The only ubiquitous response to a change in the photosynthetic pathway within Panicoideae was a niche expansion of the C4 species into regions with higher growing season temperatures, but without a withdrawal from the inherited climate niche. Other patterns varied among the tribes, as macro-climatic niche evolution in the American tribe Paspaleae differed from the pattern supported in the globally distributed tribe Paniceae and at family level. Fil: Aagesen, Lone. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Biganzoli, Fernando. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Bena, María Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Godoy Bürki, Ana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Reinheimer, Renata. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

Previous systematic treatments of Menonvillea recognized a group of six morphologically related species, the ‘M. scapigera group,' distinguished by having pinnately lobed leaves and united filaments of median staminal pairs. The number of recognized species ranged from six to two, one with three subspecies. In order to clarify the taxonomy of this group, multivariate and univariate analyses of qualitative and quantitative characters from herbarium specimens were performed. Additionally, to test the morphological results, the phylogenetic relationships and degree of exclusive ancestry were studied using ITS sequences and the genealogical sorting index. Our results support the recognition of three species (M. famatinensis, M. hirsuta, M. scapigera) delimited by a unique combination of qualitative characters. Quantitative characters support the division of the latter species into two subspecies: scapigera and longipes. The molecular data are congruent with the morphology and support the inclusion of M. hookeri within M. scapigera. A key to taxa of the M. scapigera group is presented.

Included in the PACMAD clade of the family Poaceae (Panicoideae, Arundinoideae, Chloridoideae, Micrairoideae, Aristidoideae, Danthonioideae), the tribe Paniceae s.l. is one of the largest tribes of the subfamily Panicoideae, with more than 2000 species. This tribe comprises a huge morphological, cytological and physiological diversity represented by different inflorescence types, several basic chromosome numbers, and at least four major photosynthetic pathways. The tribe Paniceae has been the subject of molecular studies that have confirmed its paraphyly: two major clades were recognized based on their basic chromosome numbers (x = 9, x = 10). The x = 10 Paniceae clade is sister to the Andropogoneae–Arundinelleae s.s. clade (x = 10), while the combined x = 10 clade is sister to the x = 9 clade that contains the remaining genera of Paniceae. As a result of a recent realignment within the tribe in terms of the phylogenetic position of minor and major Paniceae genera, a reanalysis of the whole sampling is performed and new underrepresented taxa are discussed. A total of 155 genera, currently considered within subfamily Panicoideae, are represented here by almost all genera of Paniceae s.l., representatives of Andropogoneae and Arundinelleae s.s., and the endemic and small tribe Steyermarkochloeae; we also included specimens of subfamily Micrairoideae, tribes Isachneae and Eriachneae. The sampling includes as outgroups 18 genera of the PACMAD clade (excluding Panicoideae) and four genera from the BEP clade (Bambusoideae, Ehrhartoideae, Pooideae), rooting with Bromus inermis. A matrix with 265 taxa based on the combined evidence from ndhF plastid sequences (2074 bp) and 57 morphological characters was subjected to parsimony analyses. Jackknife resampling was used to calculate group support. Most clades are characterized by morphological, cytological, anatomical, and/or physiological characters. Major tribal changes are based on the basic chromosome number; the pantropical x = 9 clade is here recognized as Paniceae s.s., while the American x = 10 Paniceae s.l. is restricted to the reinstated tribe Paspaleae. The optimization of the photosynthetic pathway for the Paspaleae–Andropogoneae–Arundinelleae s.s. clade, including the monotypic Reynaudia, shows a plesiomorphic C4 state while the ancestral state for Paniceae s.s. is ambiguous. If Reynaudia were not included or placed elsewhere, the ancestral photosynthetic pathway for both the Paspaleae–Andropogoneae–Arundinelleae s.s. clade and the Paniceae s.s. would be unambiguously C3. In order to explore character evolution further, the morphological characters were mapped onto one of the most parsimonious trees. A relationship between photosynthetic pathways and inflorescence morphology is suggested here for the first time. Based on the optimization of morphological characters and additional data, we propose names for almost all inner clades at the rank of subtribe with a few groups as incertae sedis. With this extensive sampling, we resolved the phylogenetic relationships and the assignation of synapomorphies, and improved the support in subtribe sorting; consequently a robust circumscription of the tribe Paniceae s.l. is proposed.

The idea of an area of endemism implies that different groups of plants and animals should have largely coincident distributions. This paper analyses an area of 1152 000 km2, between parallels 21 and 32°S and meridians 70 and 53°W to examine whether a large and taxonomically diverse data set actually displays areas supported by different groups. The data set includes the distribution of 805 species of plants (45 families), mammals (25 families), reptiles (six families), amphibians (five families), birds (18 families), and insects (30 families), and is analysed with the optimality criterion (based on the notion of endemism) implemented in the program NDM/VNDM. Almost 50% of the areas obtained are supported by three or more major groups; areas supported by fewer major groups generally contain species from different genera, families, or orders. © The Willi Hennig Society 2011.

The present paper includes a taxonomic revision of the genus Gymnopogon P. Beauv. (Poaceae, Chloridoideae, Cynodonteae), with a total of 14 species treated in this work, including more than 40 synonyms. The genus includes perennial, occasionally annual, species, with erect to decumbent culms, ligules membranous-ciliate, blades conspicuously distichous, inflorescences with spikelets on racemiform branches, spikelets laterally compressed, 1- to 4-flowered, glumes 1-nerved, lemma 3-nerved, awned. Species distributions are mostly American, with one Asian species. A description of morphological characters, key to identify the species, descriptions, synonymy, geographical distribution, and illustrations of characteres of taxonomic value are also included. The name Chloris delicatula C. B. Clarke ex Hook. f. (≡ Gymnopogon delicatulus (C. B. Clarke ex Hook. f.) Bor) is lectotypified.

The present treatment includes the first revision of 31 species of Axonopus P. Beauv. (Poaceae) in Argentina, southern Brazil, Bolivia, continental Chile, Paraguay, and Uruguay. A key to the species is provided, together with detailed descriptions, illustrations, distribution ranges, and a discussion of the morphological relationships of the species. Axonopus caulescens (Mez) Henrard is first reported for Bolivia, and the names A. eminens (Nees) G. A. Black and A. kleinii L. B. Sm. & Wassh. are synonymized with A. siccus (Nees) Kuhlm. and A. uninodis (Hack.) G. A. Black, respectively. The names Panicum hagenbeckianum Kuntze and Paspalum ulei Hack. are lectotypified.

Two new species of Paniceae are here described, one belonging to Dichanthelium (Dichanthelium barbadense) and the other to Panicum sect. Laxa (Panicum harleyi). Both taxa grow in open areas of Central Brazil are described, illustrated, and compared with putative related species.

Durante la preparación del fascículo Gramineae VI de la Flora del Paraguay, hemos encontrado la necesidad de corregir y precisar la tipificación de varios nombres. Los principales problemas encontrados fueron para las lectotipifiaciones, la publicación efectiva y la designación del lectótipo y para la determinación del material original, el conocimiento de la manera de trabajar de los autores y la historia de las colecciones. Fil: Ramella, Lorenzo. Conservatoire et Jardin botaniques de la Ville de Genève; Suiza Fil: Perret, Patrick. Conservatoire et Jardin botaniques de la Ville de Genève; Suiza Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Morrone, Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Pensiero, Jose Francisco. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina

As part of an ongoing revision of the genus Polygala, several names of the South Andean and Patagonian species in need of nomenclatural and taxonomic study were identified. 13 lectotypes have been designated for accepted names, synonyms and a dubious taxon.

The taxonomic features of species ofPanicum, previously classified in Panicum subg. Agrostoidea and Phanopyrum including sects. Megista, Tenera, Prionitia and Agrostoidea, are reviewed and compared with subg. Panicum and other taxa of Paniceae. All taxa, previously considered in these subgenera and sections, are now included in the new genera Stephostachys and Sorengia, which are based on morphological and molecular characters. Stephostachys includes one species, S. mertensii (Roth) Zuloaga & Morrone, ranging from Mexico to Argentina, while Sorengia comprises seven species, S. anceps (Michx.) Zuloaga & Morrone, S. caricoides (Nees ex Trin.) Zuloaga & Morrone, Sorengia longifolia (Torr.) Zuloaga & Morrone S. petensonii (Hitchc. & Ekman) Zuloaga & Morrone, S. prionitis (Nees) Zuloaga & Morrone, S. stenodes (Griseb.) Zuloaga & Morrone, and S. tenera (Beyr. ex Trin.) Zuloaga & Morrone, distributed from the United States to Bolivia and Brazil. Affinities of the new genera with other genera of Paniceae are discussed. Lectotypes are designated for Panicum caricoides var. glabriusculum Doll, P. caricoides var. pilosum Doll, P. prionitis Nees, P. prionitis var. varium Kuntze, and P. stenodes Griseb.

The subtribe Melinidinae (Poaceae: Panicoideae: Paniceae) includes 14 genera that present the PCK photosynthetic subtype in addition to several other unique and also common characters. The purpose of this research was (1) to test the monophyly of the subtribe Melinidinae, including 331 ndhF sequences of Panicoids and related genera, (2) to analyze the phylogenetic relationships among genera of Melinidinae using four cpDNA regions, and (3) to study evolutionary trends in the homogenization of inflorescences. As a result, the monophyly of Melinidinae is supported if Urochloa venosa is excluded from the subtribe. Alloteropsis semialata subsp. semialata, an unusual PCK species, is here confirmed within the Forest shade clade. Within Melinidinae, Urochloa and Eriochloa appeared as paraphyletic and polyphyletic genera, respectively. Finally, the general trend in the evolution of the inflorescences in Melinidinae seems to be the reduction from non-homogenized to complete homogenized inflorescences.

A revision of the species of Deschampsia P. Beauv., Avenella (Bluff & Fingerh.) Drejer, and Vahlodea Fr. (Poaceae, Poeae, Airinae) present in South America is given. Fifteen species of Deschampsia and two monospecific genera segregated from Deschampsia—Avenella and Vahlodea—are found in the Andes of Argentina and Chile south of 30°S, typically in humid or damp sites and wetlands. Isolated populations of the cosmopolitan D. cespitosa (L.) P. Beauv. are also found in Bolivia and highlands of southern Brazil. Keys to differentiate among the species of Deschampsia and the allied genera Avenella and Vahlodea are provided. A lectotype is designated for D. berteroana (Kunth) Trin.

Chromosome numbers and meiotic behavior of 60 individuals of American Paniceae, Poaceae, are provided, including six previously uncounted species: Axonopus andinus G. A. Black (2n = 20), A. iridifolius (Poepp.) G. A. Black (2n = 20), Dichanthelium hebotes (Trin.) Zuloaga (2n = 18), Paspalum geminiflorum Steud. (2n = ca. 20), P. heterotrichon Trin. (2n = 20), and Setaria tenacissima Schrad. ex Schult. (2n = 36). Of the remaining 54 counts, 17 correspond to new ploidy levels in species of Echinochloa P. Beauv., Eriochloa Kunth, Hymenachne P. Beauv., Panicum L., Parodiophyllochloa Zuloaga & Morrone, Paspalum L., and Setaria P. Beauv., and 37 are confirmations of previous reports.

Species related to Paspalum denticulatum Trin. are studied systematically, including taxa traditionally placed in the informal group Livida of Paspalum L. The analysis demonstrates Livida to be an artificial group, without characters that delimit it from remaining groups within Paspalum; for this reason, its species are treated as ungrouped within subgenus Paspalum. A total of 11 species are herein described, compared, and analyzed. Paspalum hieronymii Hack., P. jujuyense Zuloaga, P. lividum Trin. ex Schltdl., and P. proliferum Arechav. are maintained as synonyms of P. denticulatum. Paspalum tinctum Chase is here reduced to synonymy under P. hartwegianum E. Fourn. and P. arsenei Chase under P. pubiflorum Rupr. ex E. Fourn. Paspalum pisinnum Swallen and P. trinii Swallen are here treated under the synonymy of P. trichophyllum Henrard. Distribution maps, plates of species not previously illustrated, and SEM microphotographs of the upper anthecia are included, as well as a taxonomic key to different...

Panicum sensu stricto is a genus of grasses (Poaceae) with nearly, according to this study, 163 species distributed worldwide. This genus is included in the subtribe Panicinae together with Louisiella, the latter with 2 species. Panicum and subtribe Panicinae are characterized by including annual or perennial taxa with open and lax panicles, and spikelets with the lower glume reduced; all taxa also share a basic chromosome number of x = 9 and a Kranz leaf blade anatomy typical of the NAD-me subtype photosynthetic pathway. Nevertheless, the phylogenetic placements of many Panicum species, and the circumscription of the genus, remained untested. Therefore, phylogenetic analyses were conducted using sequence data from the ndhF plastid region, in an extensive worldwide sampling of Panicum and related genera, in order to infer evolutionary relationships and to provide a phylogenetic framework to review the classification of the genus. Diversification times, historical biogeography and evolutionary patterns of the life history (annual vs. perennial) in the subtribe and Panicum were also studied. Results obtained provide strong support for a monophyletic Panicum including 71 species and 7 sections, of which sections Arthragrostis and Yakirra are new in the genus; 7 new combinations are made here. Furthermore, 32 species traditionally assigned to Panicum were excluded from the genus, and discussed in other subtribes of Paniceae. Our study suggested that early diversification in subtribe Panicinae and Panicum occurred through the Early-Mid Miocene in the Neotropics, while the subsequent diversification of its sections mainly occurred in the Late Miocene-Pleistocene, involving multiple dispersals to all continents. Our analyses also showed that transition rates and changes between annual and perennial life history in Panicum were quite frequent, suggesting considerable lability of this trait. Changes of the life history, together with C4 photosynthesis, and the multiple dispersal events since the Mid Miocene, seem to have facilitated a widespread distribution of the genus. All these findings contribute to a better understanding of the systematics and evolution of Panicum. Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Salariato, Diego Leonel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Scataglini, María Amalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

The present contribution continues a critical revision of Panicum, particularly with the delimitation of “incertae sedis” taxa. A phylogenetic analysis of Paniceae based on cpDNA sequence data (ndhF) was performed with special emphasis on section Stolonifera of Panicum. Fourteen sequences of species of sect. Stolonifera and Echinolaena were added to a panicoid grass matrix previously published giving a total of 140 sequences. As a result, Ocellochloa is here described as a new genus including 12 new combinations: O. andreana, O. biglandularis, O. brachystachya, O. chapadensis, O. craterifera, O. irregularis, O. latissima, O. piauiensis, O. pulchella, O. rudis, O. soderstromii , and O. stolonifera. The position of Panicum venezuelae, previously placed in section Stolonifera with the above mentioned species, clearly indicates that this species is not closely related to the Ocellochloa clade. This conclusion is supported by several morphological characters, such as the presence of axillary infloresc...

Se presenta un estudio taxonómico del género Panicum para el Noreste de México, el cual incluye los estados de Coahuila, Nuevo León y Tamaulipas. La región es considerada un centro de origen y diversifi cación de plantas de las zonas áridas y semiáridas del país, donde la agricultura y la ganadería son dos actividades muy importantes. El género es el más grande de la tribu Paniceae, con distribución mundial, está representado en el área de estudio por un total de 19 especies con cuatro variedades. Se presenta además una clave para diferenciar los géneros recientemente segregados de Panicum , descripciones de las especies, distribución en México y se incluyen mapas de distribución para el área de estudio.

Rupichloa, a new genus of Paniceae restricted to Bahia and Minas Gerais, Brazil, and including two species, R. acuminata and R. decidua, is here described on the basis of morphological and molecular characters. Analyses of DNA sequence data from plastid rpl16 and ndhF indicate that the two included species do not belong to Urochloa, in which they were previously placed. The affinities of the new genus with other genera of Paniceae are discussed.

Paspalum, an American genus of the x = 10 Paniceae clade, includes about 330 species, four subgenera, and 27 informal groups. Within the genus, the Quadrifaria and Virgata groups are well-represented in South and Central America. Interspecific variability make the delimitation of these groups difficult; hence several species have been included or excluded from Quadrifaria or Virgata depending on the taxonomic treatment. In previous analyses, the Quadrifaria and Virgata groups of Paspalum were polyphyletic. Here we present a new appraisal of the classification of both groups based on the phylogenetic analyses of DNA data from the chloroplast: the rpl16 intron, and the region comprising the trnL and trnF genes. A monophyletic Virgata clade is recovered, consisting of nearly all the species listed in an unpublished manuscript. The Quadrifaria group is restricted to P. quadrifarium and P. quarinii. Other clades grouped species traditionally treated within Virgata or Quadrifaria, although their phylogenetic placement needs to be reevaluated. Within most of the clades, diploid and polyploid species seemingly derive from a common ancestor denoting an autopolyploid origin. Alloploidy is also possible although reticulate evolution needs to be explored. The wide distribution of the I genome suggests that this is a plesiomorphic state in Paspalum. Fil: Giussani, Liliana Mónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Quarin, Camilo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentina Fil: Cota Sánchez, J. Hugo. University of Saskatchewan; Canadá Fil: Ubayasena, Kumary. University of Saskatchewan; Canadá Fil: Morrone, Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

The genus Setaria is the largest genus in the so-called bristle clade, a monophyletic group of panicoid grasses distinguished by the presence of sterile branches, or bristles, in their inflorescences. The clade includes both foxtail millet and pearl millet, the latter an important cereal crop in dry parts of the world. Other members of the clade are weeds that are widespread agricultural pests. Previous molecular phylogenetic studies have suggested that Setaria might not be monophyletic but did not have a large enough sample of species to test this rigorously. In addition, taxonomic studies have suggested a close relationship between Setaria and Paspalidium, with some authors combining them into a single genus, but molecular studies included too few Paspalidium accessions for a meaningful conclusion. Accordingly, we have produced 77 new sequences of the chloroplast gene ndhF for 52 species not in previous analyses. These were added to available sequences for 35 species in 10 genera of the bristle clade and four outgroup taxa. We find that Setaria species fall into several moderately to strongly supported clades that correlate with geography but not with the existing subgeneric classification. Relationships among these clades and among other genera within the bristle clade are unclear. Constraint experiments using the approximately unbiased test reject the monophyly of Pennisetum, Setaria, and Setaria plus Paspalidium, as well as several other groupings, although the test may be overly sensitive and prone to Type I error. The more conservative Shimodaira-Hasegawa test fails to reject monophyly of any of the tested clades. Fil: Kellogg, Elizabeth Anne. University of Missouri; Estados Unidos Fil: Aliscioni, Sandra Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina Fil: Morrone, Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Pensiero, Jose Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

This paper constitutes the first report of the chemical nature, and histochemical localization of secretions in Brazilian species of Panicum L. sect. Lorea Zuloaga (Poaceae, Panicoideae, Paniceae); the study also includes an anatomical analysis. Lipid secretions were found in leaf sheaths and ligular regions. Lipids accumulate in specialized epidermal cells, at times surrounding the bases of the macrohairs, and in the mesophyll. Viscous secretions have been previously reported for P. vaginiviscosum Renvoize & Zuloaga and P. acicularifolium Renvoize & Zuloaga, species in section Lorea that are analyzed anatomically here. Lipid secretions are now also reported for the first time in eight other species of section Lorea: P. bahiense Renvoize, P. chnoodes Trin., P. cipoense Renvoize & Send., P. durifolium Renvoize & Zuloaga, P. euprepes Renvoize, P. molinioides Trin., P. poliophyllum Renvoize & Zuloaga, and P. trinii Kunth.

The tribe Stipeae occurs in temperate and warm temperate grasslands of Eurasia, Australia, and America. Although generic circumscription within the tribe has recently undergone significant changes, the American genus Piptochaetium has been clearly defined by morphological and anatomical characters. It includes 36 species and 2 varieties, most of them widely distributed in temperate grasslands of South America. Phylogenetic analyses were conducted in Piptochaetium and allied genera of the Stipeae, in order to test the monophyly of the genus, re-examine infrageneric taxa, and analyze relationships among species of this genus and allied genera of Stipeae. Two chloroplast molecular markers, trnL-F and rpl16, as well as morphology were used. Topology between morphological and molecular data mainly differs in the relationships of Piptochaetium with Anatherostipa and Piptatherum. Molecular and combined analyses yielded two major clades in the tribe: the x = 11 Clade with Piptochaetium, Aciachne, Anath...

Panicum L., as traditionally circumscribed, is one of the largest genera of Poaceae, with approximately 450 species distributed worldwide (Webster, 1988). Recent phylogenetic studies in this genus, based on morphological and molecular data have clearly shown that Panicum is a polyphyletic genus (Gomez-Martinez & Culham, 2000; Zuloaga & al., 2000; Giussani & al., 2001; Duvall & al., 2001, 2003; Aliscioni & al., 2003). As a consequence, subgenera were raised or reinstated at the generic level, such as Dichanthelium (Hitchc. & Chase) Gould, Phanopyrum Raf., Steinchisma Raf., and Meg-athyrsus (Pilg.) B.K. Simon & S.W.L. Jacobs (Zuloaga & al., 1998, 2003; Aliscioni & al., 2003; Freckmann & Lelong, 2003; Simon & Jacobs, 2003; Barkworth, 2006). At the same time, Panicum was restricted to its type subgenus (Aliscioni & al., 2003) and all remaining species classified as “incertae sedis” within Paniceae. Among these species, Panicum discrepans Doll, pre-viously classified in the monotypic sect. Discrepantia (Zuloaga, 1987), is unique by having lower glumes ab-sent or reduced, gibbous spikelet, and upper anthecium open at the apex and with long, curled macrohairs at the apex and base. A detailed discussion of relationships in Panicum , segregated genera and “incertae sedis” species can be found in Zuloaga & al. (2006).The purpose of this study is to evaluate the taxonomic position of Panicum discrepans. New molecular evidence from the ndhF (NADH dehydrogenase subunit F) gene and from the grass-specific insert in the rpoC2 (subunit C2 of an RNA polymerase) gene, together with several morphological and anatomical characters support the formation of a new genus.

Panicoideae (Poaceae) in the New World comprise 107 genera (86 native) and 1357 species (1248 native). As circumscribed herein, Panicoideae include eight tribes: Andropogoneae, Arundinelleae, Centotheceae, Gynerieae, Isachneae, Paniceae, Steyermarkochloeae, and Thysanolaeneae. The two major tribes are Andropogoneae with 230 species (16.95% of all New World panicoids), and Paniceae with 1082 species (79.73%). Andropogoneae are divided into nine subtribes (Andropogoninae, Anthistiriinae, Coicinae, Germainiinae, Ischaeminae, Rottboelliinae, Saccharinae, Sorghinae, and Tripsacinae), while Paniceae are divided into seven subtribes (Arthropogoninae, Cenchrinae, Digitariinae, Melinidinae, Panicinae, Paspalinae, and Setariinae). Brazil is the center of diversity of New World panicoids with 741 species (54.6% of all species). The distributions of endemic and restricted taxa were analyzed in terms of biogeographical regions and Kranz syndrome. Amphitropical disjuncts and widespread species are also discussed.

Onuris hauthalii is a species distributed in Southern Argentina and Chile. Its generic assignment has been controversial, being included in Eudema, Brayopsis and Onuris. In order to clarify its generic affinities, we studied its morphology and phylogenetic relationships using multilocus/multispecies coalescent species-tree analyses based on four DNA regions (ITS, trnL-F, trnH-psbA, and rps16 intron). Results show that while O. hauthalii is related to Onuris s.s., it represents a well-differentiated lineage characterised primarily by having branched rhizomes, rosette flowering with ebracteate flowers, and latiseptate silicles. Based on the morphological and molecular evidence, we place this species in the new monospecific genus Alshehbazia. A description, morphological key, updated geographical distributions, map, and illustration are provided. Fil: Salariato, Diego Leonel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

Taxonomic features of African species of Panicum sections Clavelligerae and Pectinatae are reviewed and compared with Dichanthelium and other taxa in tribe Paniceae. The new subtribe Dichantheliinae is proposed on the basis of molecular and morphological characters: it includes non-Kranz species, growing at forests edges or in mountain grasslands with membranous-ciliate ligules, lax and open inflorescences, ellipsoid to oblongoid spikelets, and an indurate upper anthecium. Within the Dichantheliinae, the new genus Adenochloa is also established on the basis of chloroplast ndhF sequences and morphological characters, i.e., plants with clavellate multicellular, and glandular hairs present on blades, main axis, branches, and pedicels of inflorescences; ellipsoid to oblongoid, glabrous spikelets, with a lower glume 1/3 to more than 1/2 the length of the spikelet; a 7–13-nerved upper glume and a 5–9-nerved lower lemma; the upper anthecium is indurate, pilose or glabrous. Adenochloa includes 14 species from Africa and Madagascar. The new combinations: Adenochloa adenophylla, A. adenophora, A. bullockii, A. claytonii, A. ecklonii, A. flacciflora, A. habrothrix, A. hymeniochila, A. lukwangulense, A. nigromarginata, A. pectinella, A. pole-evansii, A. sadinii, and A. squarrosa are proposed and the new genus is compared with other genera of the tribe Paniceae. Also, lectotypes are designated for Brachiaria sadinii, Panicum adenophorum, P. adenophyllum, P. ecklonii, P. katentaniense, P. kisantuense, P. hymeniochilum, P. hymeniochilum var. glandulosum, P. snowdenii, and P. scandens; Panicum glanduliferum and P. omega are treated as new synonyms of Adenochloa hymeniochila and A. pectinella, respectively. Finally, new illustrations are provided for 6 species of the new genus. Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Salomón, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Scataglini, María Amalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

The taxonomic revision of species of the genus Axonopus P. Beauv. series Suffulti G. A. Black is presented. This series includes perennial species, frequently growing in savannas and in grasslands, on argillaceous or sandy ground with rocky outcrops, at altitudes up to 3500 m. The plants are rhizomatous or stoloniferous, with conduplicate sheaths and narrowly linear to linear-lanceolate blades, flat to folded along their entire length, or open toward the apex. The inflorescences are exserted from the apex of the culms; they consist of spiciform racemes of variable number, mainly digitate. The rachis of each raceme is triquetrous, sinuous, with hispidulous angles, sometimes with long and rigid hairs. The upper lemma and the upper palea are indurate, dark brown, papillose, and shiny. Sixteen species are here considered within Axonopus series Suffulti, principally distributed in South America, with A. ciliatifolius Swallen and A. jeanyae Davidse endemic species of Belize and Panama, respectively. De...

Chromosome numbers and observations on meiotic chromosome behavior of 37 taxa of American Panicoideae are given. The taxa studied are: Axonopus scoparius (Flugge) Kuhlm., Cenchrus myosuroides Kunth, Dichanthelium aciculare var. aciculare (Desv. ex Poir.) Gould & C. A. Clark, D. acuminatum var. acuminatum (Sw.) Gould & C. A. Clark, Echinochloa chacoensis P. W. Michael ex Renvoize, Eriochloa montevidensis Griseb., Isachne arundinacea (Sw.) Griseb., Panicum hirticaule J. Presl, P. stoloniferum Poir., P. trichanthum Nees, Paspalum blodgettii Chapm., P. buchtienii Hack., P. caespitosum Flugge, P. candidum (Humb. & Bonpl. ex Flugge) Kunth, P. ceresia (Kuntze) Chase, P. clavuliferum C. Wright, P. commune Lillo, P. denticulatum Trin., P. ekmanianum Henrard, P. ellipticum Doll, P. fimbriatum Kunth, P. glabrinode (Hack.) Morrone & Zuloaga, P. glaucescens Hack., P. hartwegianum E. Fourn., P. inconstans Chase, P. indecorum Mez, P. juergensii Hack., P. pauciciliatum (Parodi) Herter, P. penicillatum Hook. f., ...

In a recent treatment, the genus Panicum was restricted to subgenus Panicum based on molecular, morphological, and anatomical data. Also, other species of Panicum were transferred to different genera of the Paniceae, such as Dichanthelium, Hymenachne, Phanopyrum, and Steinchisma, while the remaining American species of Panicum were temporarily placed as incertae sedis taxa. Therefore, these incertae sedis species are in need of a new taxonomic status within the tribe. In this study, the taxonomic position of Panicum aristellum, an endemic species of central and southeastern Brazil, is evaluated using morphological and anatomical characters, together with sequence data from ndhF, a molecular marker from the chloroplast. The sequence of Panicum aristellum was analyzed together with other species of the subfamily Panicoideae. This species grouped with the genus Canastra in a well-supported clade. Several synapomorphies characterized the clade: caespitose plants, keeled sheaths, aristate spikelets, scabrous bracts, the number of nerves of the glumes and lower lemma, the presence of a lower palea and lower flower, a non-indurate upper anthecium, and a similar geographical distribution. In addition, both species are C3 with non-Kranz anatomy. As a result, the new combinationCanastra aristella is proposed and the species is compared to putatively related genera within the Paniceae.

A new species, Panicum complanatum from southeastern Brazil is described and illustrated, including a key to distinguish it from similar taxa. Panicum complanatum belongs to Panicum subg. Panicum and is characterized mainly by the presence of a regular row of flattened, long hairs at the ventral base of the upper lemma and palea.

A taxonomic revision and nomenclatural update for Paspalum sect. Pectinata is presented. This section comprises seven species distributed from southern Mexico to Peru, Bolivia and southern Brazil, and is characterized by having linear to lanceolate blades, inflorescences subdigitate or conjugate with a winged rachis, and upper glume and lower lemma 3?7-nerved. We include 16 names and propose lectotypes for Paspalum aspidiotes, P. contractum, P. cordatum, P. lanciflorum and P. pectinatum. Also, after examination of herbarium specimens, a new synonym for Paspalum reticulinerve is proposed. The revision was based on a review of the relevant literature, study of types and materials from 43 herbaria. Descriptions, distribution maps, illustrations and comments are presented for each species, and a key to all species is included. Fil: Delfini Feliciano, Carolina. Universidade Estadual de Campinas; Brasil Fil: Castro Souza, Vinicius. Universidade Do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; Brasil Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

Tribe Eudemeae comprises a morphologically heterogeneous group of genera distributed along the Andes of South America from Colombia southward into southern Chile and Argentina. The tribe currently includes seven genera: Aschersoniodoxa, Brayopsis, Dactylocardamum, Delpinophytum, Eudema, Onuris, and Xerodraba, and exhibits a wide morphological diversification in growth habit, inflorescences, and fruits. However, little is known about the phylogenetic relationships and evolution of the tribe. We present here a molecular phylogeny of representative sampling of all genera, utilizing sequence data from the nuclear ribosomal ITS region and chloroplast regions trnL-F, trnH-psbA, and rps16. Additionally, climatic niches of the tribe and its main lineages, along with the evolution of diagnostic morphological characters, were studied. All analyses confirmed the monophyly of Eudemeae, with the exception of Delpinophytum that was included with genera of the lineage I of Brassicaceae. Eudemeae is divided into two main lineages differentiated by their geographical distribution and climatic niche: the primarily north-central Andean lineage included Aschersoniodoxa, Brayopsis, Dactylocardamum, and Eudema, and the Patagonian and southern Andean lineage included Onuris and Xerodraba. Finally, ancestral-state reconstructions in the tribe generally reveal multiple and independent gains or losses of diagnostic morphological characters, such as growth form, inflorescence reduction, and fruit type. Relevant taxonomic implications stemming from the results are also discussed. Fil: Salariato, Diego Leonel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Cano, Asunción. Universidad Nacional Mayor de San Marcos ; Perú Fil: Al-Shehbaz, Ihsan. Missouri Botanical Garden; Estados Unidos

An update of the nomenclature of the genera Leptocoryphium Nees and Panicum L. (Gramineae-Paniceae) of the Flora of Paraguay. Candollea 69: 89-91. In Spanish, English abstract. The accepted names of Leptocoryphium Nees and Panicum L., published in 1994 in the fascicle Flora del Paraguay 23, are revised and updated following the most recent taxonomic revisions. Fil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Morrone, Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

DNA sequence data from the chloroplast gene ndhF were analyzed to estimate the phylogeny of the subfamily Panicoideae, with emphasis on the tribe Paniceae. Our data suggest that the subfamily is divided into three strongly supported clades, corresponding to groups with largely identical base chromosome numbers. Relationships among the three clades are unclear. In unweighted parsimony analyses, the two major clades with x = 10 (Andropogoneae and x = 10 Paniceae) are weakly supported as sister taxa. The third large clade corresponds to x = 9 Paniceae. In analyses under implied weight, the two clades of Paniceae are sisters, making the tribe monophyletic. Neither resolution is strongly supported.Our molecular phylogenies are not congruent with previous classifications of tribes or subtribes. Based on this sample of species, we infer that C(4) photosynthesis has evolved independently several times, although a single origin with multiple reversals and several reacquisitions is only slightly less parsimonious. The phosphoenol pyruvate carboxykinase (PCK) subtype of C(4) photosynthesis has evolved only once, as has the NAD-malic enzyme (ME) subtype; all other origins are NADP-ME. Inflorescence bristles are apparently homologous in the genera Setaria and Pennisetum, contrary to opinions of most previous authors. Some genera, such as Digitaria, Echinochloa, and Homolepis are supported as monophyletic. The large genus Paspalum is shown to be paraphyletic, with Thrasya derived from within it. As expected, Panicum is polyphyletic, with lineages derived from multiple ancestors across the tree. Panicum subg. Panicum is monophyletic. Panicum subg. Dichanthelium, subg. Agrostoides, and subg. Phanopyrum are unrelated to each other, and none is monophyletic. Only Panicum subg. Dichanthelium sect. Dichanthelium, represented by P. sabulorum and P. koolauense, is monophyletic. Panicum subg. Megathyrsus, a monotypic subgenus including only the species P. maximum, is better placed in Urochloa, as suggested by other authors.

3-1. Panicum millegrana Poir., Encycl., Suppl. 4: 278. 1816. Sintipos: Guayana Francesa, sin localidad, hb. C. Kunth (sintipo LE-TRIN-0830.01!). Guayana Francesa. Cayenne, J. Martin s.n. (sintipo P!; isosintipo US!). Figs. 4, 5 Plantas perennes, rizomatosas. Cañas decumbentes, arraigadas y ramificadas en los nudos inferiores, apoyantes y trepadoras sobre la vegetación circundante, luego erectas, 70-150 cm de altura; entrenudos 3-20 cm de largo, cilíndricos, subleñosos en la porción basal, pilosos a glabros; nudos violáceos, pilosos a glabros. Hojas con vainas 1.8-15 cm de largo, más cortas que los entrenudos, papiloso-pilosas con pelos tuberculados caducos a glabras, con márgenes membranáceos, pestañosos; cuello glabro a densamente piloso; lígulas reducidas, 0.2-0.4 mm de largo, membranáceas y cortamente laciniadas en la porción superior, con pelos por detrás en la base de la lámina; cuello densamente piloso, con pelos blanquecinos, a glabras; láminas ovado-lanceoladas a lanceoladas, 6-14 x 1-3.8 cm, base subcordada y ligeramente asimétrica, densamente pilosa, con pilosidad estrigosa, a glabras, cara adaxial con pelos tuberculados hacia la porción basal, margen escabriúsculo, las basales ciliadas con pelos tuberculados caducos. Pedúnculo hasta 6 cm de largo. InfloInflo rescencia una panoja terminal laxa, difusa, piramidal, multiflora, 10-40 x 6-30 cm; eje prin- cipal escabroso, pulvínulos pilosos a glabros, castaños, ramificaciones opuestas o alternas, pedicelos delgados, 1.2-7 mm de largo, divergentes de las ramas. Espiguillas obovoides, 1.6-2.5 mm de largo, abiertas en la madurez, hirsutas a cortamente pilosas o glabras, verdosas, castañas en la madurez, regularmente distribuidas sobre las ramificaciones. Gluma inferior 1-1.7 mm de largo, 1/3 a 1/2 o poco más del largo de la espiguilla, 1(-3)-nervia, aguda a atenuada. Gluma superior 1.7-2.2 mm de largo, sin cubrir totalmente el antecio superior, de ápice obtuso, 5-nervia, con nervio medio escabroso en su tercio superior. Lema inferior tan larga como la espiguilla, 5-nervia. Pálea inferior ovado-lanceolada, reducida, 1-1.5 x 0.4-0.6 mm, membranácea, glabra. Antecio superior ovoide, 1.6-2.2 x 0.9-1.2 mm, glabro, endurecido, castaño, transversalmente rugoso y con micropelos bicelulares en toda su superficie, ápice agudo e incurvo. Cariopsis obovoide, 1.1-1.3 x 0.8-1 mm de ancho; hilo punctiforme, embrión menos de la mitad del largo de la cariopsis. Hábitat y distribución. Panicum millegrana crece desde México hasta Argentina. En Colombia se encuentra en las regiones Andina y Caribe, incluyendo la Sierra Nevada de Santa Marta. Es frecuente en márgenes de selvas, bordes de camino y campos de cultivo y crece desde el nivel del mar hasta 2000 m de altitud. Especímenes representativos. Cesar: Rincón Hondo, Magdalena Valley, s.f., Allen 249 (MO). Cundinamarca: municipio Pandi, vereda El Caracol, 1500 m, 29 jul 1981, Díaz-Piedrahita 3292 (COL). Magdalena: Sierra Nevada de Santa Marta, at the edge of forest between Quebrada Botella and Finca Los Arroyitos, 1700 m, Kirkbride Jr. 2224 (MO). Sin localidad, 1200-1500 m, 1859, Lindig 1065 (COL); Santa Marta, 153 m, 19 dic 1903, Smith 168 (COL, NY, P, US); Santa Marta, ca. 1300 m, 19 dic 1903, Smith 2146 (COL, F, G, NY, P, US).

8-2. Panicum tricholaenoides Steud., Syn. Pl. Glumac. 1: 68. 1853. Tipo: Uruguay. Montevideo: Montevideo, Deloche 166 (holotipo W!). Figs. 19, 20 Plantas perennes, robustas, rizomatosas, con rizomas cubiertos de catafilos cortamen- te pilosos en los márgenes. Cañas erguidas, 150-200 cm de altura, en fascículos de numerosas cañas congestas, subleñosas, densamente ramificadas en los nudos medios y supe- riores; entrenudos 10-30 cm de largo, cilíndricos, huecos, pajizos, glabros; nudos glabros, oscuros. Hojas con vainas de 7-14 cm de largo, menores que los entrenudos, afilas en la base de las cañas o con láminas sumamente reducidas, esparcidamente papiloso-pilosas a glabras, cuando secas persistentes y de un color pajizo intenso; lígulas membranáceas en la base y luego cortamente ciliadas, reducidas, 0.5-1.5 mm de largo; cuello glabro, castaño a violáceo; láminas lanceoladas, 12.5-40 x 0.2-0.5 cm, de ápice subulado, base redondeada, plana o con los márgenes algo involutos, escabrosos, ciliados hacia la porción basal, cara adaxial densamente pilosa hacia la base, cara abaxial esparcidamente pilosa a glabra. Inflorescencia una panoja terminal laxa, difusa, 20-40 x 5-20 cm, erecta o subnutante; eje principal cilíndrico hacia la base, luego anguloso, escabroso, pulvínulos pilosos, castaños, ramificación inferior subverticilada, ramificaciones superiores alternas u opuestas; pedicelos claviformes, 0.5-3.4 mm de largo, con largos pelos blanquecinos persistentes. Espiguillas largamente ovoides, 2.2-2.9 x 0.8-1 mm, abiertas en la madurez, glabras, pajizas y con tintes violáceos, glumas y lema inferior cortamente pilosas o escabrosas en la cara interna. Gluma inferior ovado-lanceolada, 1.5-2.2 mm de largo, glabra, ápice acuminado a agudo, 5-7-nervia, con nervio medio escabroso. Gluma superior ovado-lanceolada, 1.8-2.6 mm de largo, acuminada a aguda, 7-9-nervia. Lema inferior glumiforme, 1.9-2.5 mm de largo, acuminada. Pálea inferior elíptica, 1.6-2 x 0.8-1 mm, membranácea, glabra. Flor inferior estaminada. Antecio superior angostamente ovoide, 1.6-1.8 x 0.7 mm, glabro, pajizo, con manchas negruzcas en la madurez, lustroso, liso, obtuso; pálea superior con papilas compuestas en su ápice, lema superior 7-nervia, con un disco oscuro en su base. Cariopsis elipsoide, 1.3-1.5 x 0.8 mm, castaña; hilo obovado, embrión más de la mitad del largo de la cariopsis. Hábitat y distribución. Habita desde Colombia y Venezuela hasta Bolivia, sur de Brasil, Paraguay, Uruguay y Argentina. Panicum tricholaenoides se encuentra en Colombia en la región Orinoquia, comúnmente en suelos arenosos, junto a cursos de agua o lagunas, de tierras bajas (± 500 m de altitud). Las cañas altas y ramificadas forman agre- gaciones densas que generalmente se encuentran apoyadas sobre matorrales. Comentarios. Esta especie se caracteriza por poseer cañas lignificadas, con aspecto bambusoide, que están ramificadas hacia los nudos medios. Especímenes representativos. Casanare: corregimiento Villanueva, caserío Caribayona, 360 m, 6 feb 1979, Rangel 2071 (COL); caño Cancia, 23 km SW de Hato Yarumito, 36 km S de Mani, 23 feb 1971, Sastre 830 (COL). Meta: los Llanos, río Meta, María, 130 m, 17 oct 1938, Cuatrecasas 3729 (COL, F, US); 2 km E of Puerto Gaitán in the flood plain of Río Manacacías, 150 m, 31 dic 1973, Davidse 5416 (COL, MO, NY); sabanas de El Vergel, 31 ene 1937, García-Barriga 4984 (COL); llano San Martín, s.f., Triana 351 (P, US); Puerto Gaitán, río Manacacías, a orillas del río, 250 m, 14 jun 1989, Zuloaga 3981 (COL, MO, SI).

4-6. Panicum hispidifolium Swallen, Contr. U.S. Natl. Herb. 29 (9): 424. 1950. Tipo: Honduras. El Paraíso: Güinope, 1 ene 1944, J. V. Rodríguez 1981 (holotipo US-1869144!; isotipos F-1166244!, F-1306220!). Figs. 10, 11 Plantas anuales, herbáceas. Cañas cespitosas, erguidas, 20-100 cm de altura, geniculadas o no en los nudos inferiores; entrenudos cilíndricos, huecos, 4-15 cm de largo, 0.1-0.4 cm de diámetro, hirsutos, con pelos tuberculados caedizos; nudos pilosos, violáceos. Hojas con vainas 4-13 cm de largo, menores o mayores que los entrenudos, densamente hirsutas, con largos pelos tuberculados, los márgenes pestañosos; lígulas cortamente membranáceas en la base, luego largamente ciliadas, 2-3 mm de largo; cuello piloso, violáceo; láminas linear-lanceoladas, 8-45 x 0.8-1.3 cm, planas, herbáceas, acuminadas, subcordadas o de base redondeada, hirsutas, con márgenes escabrosos, ciliados hacia la base, el nervio medio manifiesto. Pedúnculos incluidos en las vainas foliares a exertos, hasta 40 cm de largo, cilíndricos, hirsutos. Inflorescencia terminal exerta; panojas laxas, difusas, piramidales, multifloras, 12-50 x 10-40 cm; eje princi- pal anguloso, híspido, cubierto de gruesos pelos de base tuberculada, glabro hacia la porción superior de la panoja, ramificaciones opuestas o alternas, las inferiores ocasio- nalmente subverticiladas, divergentes, hasta 17 cm de largo, ejes de las ramificaciones híspidos; pedicelos largos, 0.5-2.5 mm de largo, escabrosos; inflorescencias axilares presentes, semejantes a la terminal. Espiguillas ampliamente elipsoides, globosas, abiertas en el ápice, 3.2-3.7 x 1.2-1.6 mm, solitarias, glabras, verdosas y con tintes violáceos, agudas a acuminadas, glumas y lema inferior con nervios marcados; gluma superior y lema inferior subiguales y superando hasta 0.3 mm en longitud al antecio superior. Gluma inferior ovada, 2-2.6 mm de largo, 1/2-3/4 del largo de la espiguilla, aguda, 5-nervia, el nervio medio escabroso, escabriúscula hacia el ápice de la cara interna. Gluma superior ca. del largo que la espiguilla, aguda, persistente en la madurez, 7-nervia, el nervio medio escabriúsculo hacia el ápice, escabriúscula en el ápice de la cara interna; gluma inferior y superior separadas por un corto entrenudo ca. 0.3 mm de largo. Lema inferior glumiforme, 7-9-nervia, aguda, pilosa en el ápice de la cara interna. Pálea inferior ovado-lanceolada, reducida, 1.6-1.8 x 0.6-0.9 mm, hialina, los márgenes superiores esparcidamente pilosos a glabros, glabra en el resto de la superfi- cie. Antecio superior aampliamente ovoide, 2.1-2.5 x 1.2-1.5 mm, crustáceo, glabro, liso, lustroso, con tintes grisáceos en la madurez y un anillo discoide en la base, castaño en la madurez; lema superior 7-nervia; pálea superior con papilas verrugosas hacia el ápice. Cariopsis ampliamente ovoide, 1.6-1.8 x 1.1-1.3 mm; hilo punctiforme, embrión menos de la mitad del largo de la cariopsis. Hábitat y distribución. Esta especie se halla desde México y América Central hasta Colombia y Venezuela. Panicum hispidifolium se encuentra en Colombia en la región Caribe, creciendo en sabanas y, frecuentemente, en las márgenes de los caminos. Comentarios. Panicum hispidifolium es afín a P. hirticaule, de la que se diferencia por poseer espiguillas globosas de mayor tamaño, no adpresas y distantes, por tener inflo- rescencias difusas que alcanzan aproximadamente 1/2 del largo total de la planta y lígulas de 2-3 mm de largo. Especímenes representativos. Atlántico: Puerto Colombia, s.f., Hitchcock 9927 (US). Magdalena: Santa Marta, 19 dic 1903, Smith 2152 (COL, F, G, GH, K, MO, NY, P, US).

9-3. Panicum hylaeicum Mez, Notizbl. Bot. Gart. Berlin-Dahlem 7: 75. 1917. Tipo: Brasil. In vicinibus Santarem, ago 1850, R. Spruce 26 (holotipo M!; isotipos K!, P!, US!). Figs. 22, 23 Plantas perennes, robustas. Cañas rígidas, arraigadas y ramificadas en los nudos in- feriores, luego erguidas, apoyantes en la vegetación, 100-200 (-300) cm de altura, plurinodes; entrenudos cilíndricos, subleñosos, 4-20 cm de largo, huecos, glabros, verdosos a purpúreos; nudos glabros, violáceos. Hojas con vainas iguales o más cortas que los entrenudos, 3.5-10 cm de largo, pajizas a violáceas, pilosas a glabrescentes, papilosopilosas con pelos caducos en los márgenes superiores; lígulas membranáceas, laciniadas a cortamente pilosas en la porción superior, 0.3-0.7 mm de largo; cuello piloso; láminas ovado-lanceoladas, 7-26 x 1-3 cm, cordadas, amplexicaules, cortamente pseudopecioladas, densamente pilosas o glabras en ambas superficies, márgenes inferiores largamente ciliados, el resto escabroso; nervios laterales anastomosados. Inflorescencias terminales, exertas o parcialmente incluidas en las hojas superiores; panojas difusas a contraídas, 10- 32 x 4.5-17.5 cm; eje principal escabroso, anguloso; pulvínulos cortamente pilosos; rami- ficaciones de primer orden alternas a opuestas, divergentes; ejes de las ramificaciones y pedicelos escabrosos; espiguillas dispuestas unilateralmente sobre ejes cortos de segundo o tercer orden; pedicelos 0.5-1.3 mm de largo. Espiguillas angostamente elipsoides, 1.4- 1.7 x 0.4-0.6 mm, biconvexas, híspidas, con pelos caducos, o glabras. Gluma inferior ovada, 0.7-1 mm de largo, ca. de ½ del largo de la espiguilla, 3-nervia, nervio medio escabroso en la porción superior. Gluma superior 1-1.7 mm de largo, cubriendo o no el antecio superior, obtusa, 5-nervia. Lema inferior aguda, 5-nervia. Pálea inferior elíptica, 0.9-1.3 x 0.3-0.5 mm, membranácea, reducida en algunos especímenes. Flor inferior estaminada. Antecio superior elipsoide, 1-1.4 x 0.4-0.6 mm, parcialmente endurecido, escabroso en la porción superior, liso, lustroso, glabro. Cariopsis 0.9 x 0.5 mm; hilo punctiforme, embrión menos de ½ del largo de la cariopsis. Hábitat y distribución. Panicum hylaeicum se encuentra en México, Mesoamérica, Cuba, República Dominicana, y desde Colombia hasta Argentina. En Colombia está en la Orinoquia y el valle del río Magdalena, habitando principalmente en márgenes de ríos y pantanos, o en suelos húmedos de márgenes de bosque, entre el nivel del mar y 1500 m de altitud. Sus cañas altas y ramificadas se apoyan en la vegetación circundante. Comentarios. Panicum hylaeicum frecuentemente es confundida con P. polygonatum Schrad., de la que se distingue por sus hojas amplexicaules, sus espiguillas con una pálea inferior bien desarrollada y una flor inferior estaminada. En P. hylaeicum se presenta una variación marcada en la pilosidad de las espiguillas, desde densamente pilosas a glabras. Cabe destacar que las plantas sudamericanas de esta especie son más grandes que las mesoamericanas, siendo éstas últimas comúnmente de hábito reptante. Especímenes representativos. Casanare: río Casanare, barranco de Atahuarpa, 120 m, 30 oct 1938, Cuatrecasas 4238 (COL), 4284 (COL, US). Meta: los Llanos, río Meta, Orocué, 140 m, 3 nov 1938, Cuatrecasas 4432 (COL, US). Santander: Puerto Arturo, Pérez 1034 (HUA).

9-8. Panicum stevensianum Hitchc. & Chase, Contr. U.S. Natl. Herb. 17 (6): 498, f. 76. 1915. Tipo: Puerto Rico. Campo Alegre, near Laguna del Tortuguero, 25 nov 1913, A. Chase 6616 (holotipo US-693323!; isotipos NY!, US!). Fig. 30 Plantas de duración indefinida, probablemente perennes. Cañas postradas, decumbentes y enraizando en los nudos inferiores, luego erectas, 20-100 cm de altura, entrenudos glabros, nudos castaños, glabros. Hojas con vainas estriadas, glabras o esparcidamente papiloso-pilosas con pelos caducos, un margen ciliado hacia el ápice, cuello castaño, glabro; lígulas membranáceas, cortamente ciliadas en el ápice, 0.4-1 mm de largo; láminas lanceoladas, 10-25 x 0.5-1.7 cm, subcordadas a cordadas en la base, los márgenes inferiores ciliados a esparcidamente pilosos en la cara adaxial o completamente glabros. Inflorescencia una panoja terminal, laxa a contraída, 8-28 x 1-6 cm; eje principal sinuoso, escabroso, ramificaciones de primer orden alternas, ejes de las ramificaciones y pedicelos escabrosos, espiguillas secundas o dispuestas en ramificaciones cortas de segundo orden, pareadas en cortos pedicelos. Espiguillas estrechamente elípticas, 1.9- 2.6 x 0.6-0.7 mm, verdosas o con tintes purpúreos, glabras, biconvexas, gluma superior y lema inferior subiguales o la gluma superior un poco más corta. Gluma inferior 0.8-1.1 mm de largo, ca. de 1/2 de la longitud de la espiguilla, acuminada, 3-nervia. Gluma superior 5-nervia. Lema inferior 5-nervia. Pálea inferior lanceolada, 2 x 0.6 mm, hialina, los márgenes escabriúsculos. Flor inferior perfecta o estaminada u ocasionalmente ausente, lodículas truncadas, anteras 1.2 mm de largo, estigma purpúreo. Antecio superior estrechamente ovado, 1.7-1.9 x 0.5 mm, blanquecino, firmemente membranáceo, glabro, escabroso en el ápice, el resto de su superficie papilosa y con cuerpos de sílice. Cariopsis no vista. Hábitat y distribución. Panicum stevensianum se distribuye en algunas islas del Caribe (Cuba, Puerto Rico y Guadalupe) y el norte de Sudamérica (Colombia, Venezuela y nordeste de Brasil), en hábitats abiertos y húmedos de zonas bajas. En Colombia se conoce sólo de un registro en la región Orinoquia (departamento de Casanare). Comentarios. Panicum stevensianum es la única especies de las aquí documentadas que puede presentar flor inferior perfecta (además de estaminada o ausente). Una ilustra- ción de esta especie puede encontrarse en Zuloaga et al. (1992). Especímenes representativos. Casanare: ca. del Hato Gandul, al sur del río Pauto, llanura aluvial de desborde, 1 feb 1964, Blydenstein s.n. (SI, US).

2. Panicum sect. Dichotomiflora (Hitchc.) Honda, J. Fac. Sci. Uni. Tokyo, Sect. 3, Bot. 3 (2): 246. 1930. Especie tipo. Panicum dichotomiflorum Michx. Plantas anuales o perennes. Cañas decumbentes a erguidas. Hojas con lígulas membranáceo-ciliadas; láminas lanceoladas. Inflorescencias laxas, difusas a contraídas, pedicelos cortos a largos. Espiguillas elipsoides a lanceoladas, glabras, dispuestas en rami- ficaciones multilaterales. Gluma inferior 1/5 a 1/3 del largo de la espiguilla, 1-3-nervia. Gluma superior y lema inferior subiguales, 5-7(-9)-nervias. Antecio superior cartilaginoso, glabro, pálea con papilas hacia la porción superior. Cariopsis elipsoide o fusiforme; hilo oblongo, embrión la mitad o menos de la mitad del largo de la cariopsis. Composición y distribución. Sección con aproximadamente diez especies en América, que crecen desde Estados Unidos de América, México, Mesoamérica y las islas del Caribe hasta Sudamérica. Incluye especies palustres, acuáticas o de suelos húmedos, habitando usualmente en terrenos abiertos y húmedos o en riberas de diferentes cursos de agua. Comentarios. Plantas C4, Kranz del subtipo anatómico PS (= XyMS+), PCK; número cromosómico básico x = 9. Clave para las especies de Panicum sect. Dichotomiflorapresentes en Colombia 1. Plantas anuales, cañas delgadas; espiguillas largamente ovoides, de (2)2.4-3 mm de largo; antecio superior casi igual al largo de la espiguilla............................................................................................................................. 2-1. Panicum dichotomiflorum 1. Plantas perennes, cañas suculentas; espiguillas lanceoladas de (3.3-) 4.5-5.6 mm de largo; antecio superior aproximadamente 3/4 del largo de la espiguilla............................................................................................................... 2-2. Panicum elephantipes

6-1. Panicum arundinariae Trin. ex E. Fourn., Mexic. Pl. 2: 25. 1886. Sintipos: México. Absque loco, s.f., C. J. W. Schiede s.n. (sintipo P!; isosintipo US-80474!). México. San Luis Potosí, s.f., Virlet 1302 (sintipo P!). México. Mirador, s.f., F. M. Liebmann 423 (sintipo US!). México. Consoquitla, s.f., F. M. Liebmann 424 (sintipo US!). México. Orizaba, s.f., Mueller 2018 (sintipo NY!). México. Córdova, s.f., Schaffner 276 (sintipo P!). México. Córdova, s.f., Schaffner 279 (sintipo P!). Fig. 16 Plantas perennes. Cañas ascendentes, arraigadas o no en los nudos inferiores, geniculadas, 25-100 cm de altura, apoyantes en la vegetación, ramificadas en los nudos superio- res; entrenudos 3-6 cm de largo, cilíndricos a comprimidos, rígidos, pubescencentes hacia los nudos o glabros; nudos oscuros, pubescentes o glabros. Hojas con vainas 3-5 cm de largo, mayores o menores que los entrenudos, cortamente pestañosas en los márgenes superiores, glabras en el resto de la superficie; lígulas reducidas, 0.4-0.6 mm de largo, membranáceas y cortamente ciliadas en la porción superior; cuello cubierto de largos pelos blanquecinos; láminas linear-lanceoladas, 7-9 x 0.5-0.8 cm, planas, de base redondeada, simétricas, con pseudopecíolo corto, los márgenes escabrosos, engrosados, cara adaxial con pilosidad estrigosa, ralamente escabriúscula, cara abaxial glabra a ralamente estrigosa, ápice acuminado. Inflorescencias terminales, exertas; panojas contraídas, paucifloras, 2-8 x 1-4 cm; eje principal escabroso, híspido o glabrescente, anguloso, pulvínu- los pilosos, ramificaciones de primer orden algo divergentes o más comúnmente adpresas al eje principal, alternas, cortas, eje de las ramificaciones híspido o glabro, pedicelos cor- tos, escabrosos y pilosos. Espiguillas elipsoides, 1.7-2.2 x 0.9-1 mm, glabras, verdosas, obtusas, gluma superior y lema inferior subiguales. Gluma inferior 0.4-0.6(-0.9) mm de largo, enervia a 1-3-nervia, aguda, hialina. Gluma superior y lema inferior 5-nervias, obtusas. Pálea inferior ausente. Antecio superior elipsoide, 1.5-1.7 x 0.7-0.9 mm, piloso, con largos pelos blanquecinos esparcidos, liso, pajizo, endurecido, lema superior cubriendo con márgenes amplios a la pálea superior; micropelos bicelulares fusiformes presentes sobre la pálea superior. Cariopsis elipsoide, 1 x 0.8 mm; hilo punctiforme, embrión la mitad del largo de la cariopsis. Hábitat y distribución. Panicum arundinariae se distribuye desde México hasta Perú y Venezuela. En Colombia está en la región Andina, departamento de Cauca, creciendo en márgenes de selvas y lugares parcialmente sombríos y húmedos, entre 1000 y 2000 m de altitud. Comentario. Una ilustración de esta especie puede encontrarse en Pohl (1980). Especímenes representativos. Cauca: El Tambo, von Sneidern 1300 (GH); between Piendamó and Silvia, Wood 4888 (K); de El Estrecho a Balboa, a 18 km de El Estrecho, 1280 m, 27 jun 1989, Zuloaga 4243 (COL, SI).

9-7. Panicum scabridum Döll, Fl. Bras. 2 (2): 201. 1877. Sintipos: Brasil. Amazonas: Manaos, Campo de Jauari, R. Spruce 1281-3 (sintipo KR; isosintipos K!, P!, US!, fragmento ex K). Brasil. Amazonas: sin localidad, R. Spruce 1381-3 (sintipo, US-81098!, fragmento ex K, P). Figs. 28, 29 Panicum manacalense Swallen, Phytologia 14: 77. 1966. Tipo: Venezuela. Amazonas: margins of Río Atabapo at Manacal, 12 jun 1959, J. J. Wurdack & L. S. Adderley 42986 (holotipo US-2307255!; isotipos F!, GH!, K!, MO-2881353!, NY!, US-2854706!, VEN!). Plantas perennes. Cañas erectas, 50-110 cm de altura, profusamente ramificadas en los nudos superiores, entrenudos cilíndricos a comprimidos, 10-15 cm de largo, sólidos hacia la base, o huecos, nudos comprimidos, oscuros, glabros. Hojas con vainas más cortas que los entrenudos, 6-8 cm de largo, cortamente ciliadas en los márgenes superiores, glabrescentes a completamente glabras; lígulas membranáceo-ciliadas, 0.2-0.6 mm de largo; láminas linear-lanceoladas, 10-21 x 0.3-1 cm, esparcidamente pilosas hacia la base de la cara adaxial, glabras en el resto de su superficie, los márgenes escabriúsculos. In- florescencia una panoja multiflora, 7-20 cm de largo, estrechamente ovada; pedúnculos 9-23 cm de largo, glabros, eje principal glabro, ocasionalmente con largos pelos, sinuosos; ramificaciones ascendentes a laxas, escabrosas; espiguillas solitarias, dispuestas en pedicelos capilares, sinuosos, elongados, algunas veces flexuosos y escabrosos; pedice- los ocasionalmente pilosos con largos pelos blanquecinos. Espiguillas 1.3-1.8 x 0.6-0.8 mm, biconvexas, ovoides, glabras, estramíneas, fuertemente nervadas. Gluma inferior 0.6-1.1 mm de largo, 1/2 de la longitud de la espiguilla o un poco más, ovada-triangular, aguda, 3-nervia, nervios anastomosados en el ápice. Gluma superior tan larga como la espiguilla, ovada, aguda, cortamente puntiaguda, 5-nervia. Lema inferior casi tan larga como la espiguilla, ovada, aguda, 3-5-nervia. Pálea inferior ausente. Antecio superior 1.1-1.4 x 0.5-0.6 mm, elipsoide, agudo, endurecido, glabro, liso, brillante, con papilas simples en el ápice de la lema y la pálea superiores. Cariopsis elipsoide, 0.9 x 0.5 mm, negruzca; hilo punctiforme, embrión menos de la mitad de la longitud de la cariopsis. Hábitat y distribución. Panicum scabridum es una especie sudamericana presente en Colombia, Venezuela, Bolivia, las guyanas y el norte de Brasil. En Colombia está en la región Orinoquia, creciendo en ambientes abiertos de tierras bajas y sujetos a humedad permanente como riberas de ríos y arroyos. Comentarios. Panicum scabridum es frecuentemente confundida con Steinchisma laxa (= P. laxum), en virtud de su hábito similar, tipo de lígula e inflorescencia, por la gluma inferior 3-nervia que alcanza 1/2 de la longitud de la espiguilla y por la gluma superior y la lema inferior subiguales y 5-nervias. No obstante, difiere por presentar el antecio superior endurecido y liso, con papilas simples hacia el ápice, pero sin aguijones ni cuerpos de sílice y la cariopsis negruzca. Especímenes representativos. Meta: 10 km W of Puerto Gaitán along road to Puerto López, along flood plain of Río Yucao, 150 m, 31 dic 1973, Davidse 5444 (COL, K, MO, US); Puerto Gaitán, 4 km al W en la vía a Puerto López, margen de arroyo, 14 jun 1989, Zuloaga 3984 (COL, MO, SI).

9-1. Panicum grande Hitchc. & Chase, Contr. U.S. Natl. Herb. 17 (6): 529, f. 143. 1915. Tipo: Panamá. Canal Zone, in the water of a swamp along the margin of Gatun Lake, 15 dic 1911, A. S. Hitchcock 9178 (holotipo US-693329!; isotipos F!, G!, ISC, K!, LL, MO!, NY!, P!, SI!, US-693330!, US-693331!, W!). Figs. 21, 22 Plantas perennes, robustas, acuáticas. Cañas decumbentes y arraigadas en los nudos inferiores, luego erectas, 100-300 cm de altura; entrenudos huecos, cilíndricos, glabros; nudos oscuros, densamente pilosos, con pelos cortos, adpresos. Hojas con vainas glabras; lígulas 1-3 mm de largo, membranáceo-ciliadas, porción membranácea 0.5-2.4 mm de largo, cilios 0.4-0.8 mm de largo; láminas lanceoladas, 50-70 x 2.5-4 cm, planas, hirsutas con pelos tuberculados cortos en la cara adaxial o densamente híspidas hacia la base de la cara adaxial o glabras, base angostada. Inflorescencia terminal exerta, pedúnculo cilíndrico, 10-30 cm de largo; panoja ovada, multiflora, 30-70 cm de largo; eje principal anguloso, escabroso, ramificaciones divergentes a ligeramente ascendentes, las inferiores verticiladas o alternas, el resto alternas, espiguillas congestas sobre las ramificaciones, pedicelos flexuosos, escabrosos. Espiguillas largamente elipsoides, 2.3-2.8 x 0.6-0.8 mm, glabras. Gluma inferior 1-1.9 mm de largo, 1/2 a 4/5 del largo de la espiguilla, lanceolada a angostamente ovada, 1-3-nervia, nervio medio escabriúsculo, con un entrenudo pequeño entre la inserción de la gluma inferior y la superior. Gluma superior casi tan larga como la espiguilla, 5-nervia, nervio medio escabriúsculo, aguda, pilosa hacia el ápice en la cara interna. Lema inferior lanceolado-ovada, tan larga como la espiguilla, 5-nervia. Pálea inferior ausente. Antecio superior angostamente elipsoide, 1.6- 1.8 x 0.6-0.8 mm, endurecido, liso, lustroso, con micropelos bicelulares hacia el ápice de la lema. Cariopsis obovoide, 1.2 x 0.6 mm; hilo punctiforme. Hábitat y distribución. Panicum grande es una especie neotropical y se distribuye desde México hasta Brasil y Bolivia. En Colombia se encuentra en las regiones Caribe, Pacífica y en el valle del río Magdalena, siendo frecuente en riberas de pantanos y arroyos de tierras bajas. Comentarios. Esta especie se caracteriza por ser acuática y con cañas robustas de hasta de 3 m de altura, las que usualmente forman agrupaciones densas flotantes. Especímenes representativos. Bolívar: Cañabetal, s.f., Pennell 3866 (GH, NY). Santander: Puerto Wilches, s.f., Killip 14786 (NY, US). Valle del Cauca: costa del Pacífico, río Yurumangui, Veneral, s.f., Cuatrecasas 16154 (F).