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The MeOH extract from dried aerial parts of Oxypetalum caeruleum (Apocynaceae) plants yielded seventeen compounds, including four new tetracyclic triterpenoids, one pregnane glycoside, two lignane glycosides, and ten known compounds. The structures of the new compounds were established using NMR, MS spectroscopic analysis and chemical evidence.

The flowers of Apocynaceae are considered as the most complex among the angiosperms, due to the occurrence of synorganization culminated in the origin of a new floral structure, the gynostege, formed by the union of androceu and gynecium, which guarantees an optimization in the reproduction process. The gynostegium is widespread in the genera of the subfamily Asclepiadoideae, being cited as an artifact of taxonomic significance in the group. Oxypetalum R.Br. It is the largest neotropical genus of Asclepiadoideae and is included in Clado MOOG, which presenting difficulties regarding the taxonomic positioning of its species. Few studies have investigated the floral anatomy of Oxypetalum and these did not address the taxonomic significance of the anatomy of the gynostegium in resolving the positioning of individuals in the group. This work seeks to investigate the anatomy of the gynecium and the gynecium of Oxypetalum appendiculatum in order to contribute to the group's taxonomy. With this, we seek to show key anatomical parameters for the easy identification of gaps in that group. Buds and flowers at pre-anthesis, anthesis, and post-anthesis were collected to analyze histologically. Material was fixed in karnovsky’s solution and gradually dehydrated in an ethanol series. Samples were infiltrated, and embedded in hydroxyethyl methacrylate. Circa 5 µm cross and longitudinal sections were cut using a rotary microtome, stained with Toluidine Blue O. All the slides were analyzed with optical and stereo microscopes and images were captured with a photomicroscope or a trinocular photo stereomicroscope. Gynoecium comprises two carpels fused at style and style head, with free ovaries. The five receptive parts of stigma are located on the gynostegium, more precisely behind the translators. At a higher level, the stigma begins to divide, appearing bifid, towards the apex. The gynoecium of Oxypetalum appendiculatum is an extremely complex structure due to the synorganization that occurred between the corona, the anthers and the gynecium itself. The result of this union is the gynostegium, which provides morphoanatomical characters that assist in delimiting this taxon and other species of this genus.

Ethnopharmacological relevance The medicinal plant Sedum oxypetalum Kunth (Crassulaceae), locally known as Jiote or in general Siempreviva (always alive) has been traditionally used by people of the Mexican community of Tenango del Valle as a home remedy to treat periodontal diseases, inducing teeth strengthening. Consequently, the aim of this work was to investigate its capacity directed to mineralized tissues regeneration. Materials and methods The aerial parts of the plant were processed and its aqueous extract (AE) was chemically characterized. The AE and its components sedoheptulose and syngenite were tested for either osteogenic differentiation or mineral-nucleation induction respectively. Results The AE and one of its components (sedoheptulose) were shown to promote the proliferation and/or osteogenic differentiation by Human Periodontal Ligament-Derived Cells (hPDLs), while inducing the mineralization process. The AE also promoted the nucleation of octacalcium phosphate and its component syngenite, the hydroxyapatite crystals formation in vitro. Conclusion The findings reported herein support the traditional use of S. oxypetalum due to its potential capacity to promote the regeneration of mineralized tissues.

Fil: Keller, Héctor A. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina. Fil: Keller, Héctor A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica del Nordeste; Argentina. Oxypetalum venustum H. A. Keller (Apocynaceae: Asclepiadoideae: Asclepiadae: Oxypetalinae), una especie similar a O. fontellae S. A. Cáceres, se describe e ilustra sobre la base de un ejemplar hallado en la provincia de Corrientes. Además, se proponen dos nuevos sinónimos y se presenta una clave para identificar las especies hasta ahora documentadas para la Argentina. Oxypetalum venustum H. A. Keller (Apocynaceae: Asclepiadoideae: Asclepiadae: Oxypetalinae) is described and illustrated based on a specimen found in Corrientes Province. Moreover, two new synonyms are proposed, and an identification key to the species currently documented for the Argentinian flora is provided.

A new species, Oxypetalum marchesii, from rocky grassland environments of Uruguay, is here described, illustrated, and compared to morphologically similar species. Data on its habitat, distribution, ecology, and conservation status are also provided. Based on its cpDNA, O. marchesii clearly corresponds to the recently re-circumscribed and morphologically diverse genus Oxypetalum. This species is mostly characterized by its creeping, non-twining habit, widely ovate and shortly petiolate hirsute leaves, relatively large flowers with pale greyish corollas, and short stylar-head appendage that is included within a corona formed of oblong-lanceolate, bifurcate lobes. The conservation status of this species is considered vulnerable because of its small geographic range and restricted population size. Fil: González, Andrés. Museo Nacional de Historia Natural. Departamento de Botánica; Uruguay Fil: Fernández, Martina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Ezcurra, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

Sobre la base de un ejemplar de herbario recolectado a 1100 m.s.n.m., en el estado de Santa Catarina, Brasil, se describe e ilustra una nueva especie del género Oxypetalum R. Br. (Apocynaceae). Se provee información sobre su estado de conservación y se brindan observaciones ecológicas. Se discuten las similitudes y diferencias con especies afines. Based on herbarium material collected at 1100 m.a.s.l. in the Santa Catarina State, Brazil, a new species of Oxypetalum R. Br. (Apocynaceae) is here described and illustrated. Its conservation status is assessed and information on its ecology are provided. Similarities and differences with related species are discussed Fil: Keller, Hector Alejandro. 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: Funez, Luis A.. Universidade Regional de Blumenau; Brasil

Oxypetalum is the largest genus of Oxypetalinae (Apocynaceae-Asclepiadoideae) and presents its highest diversity in southern South America. A new species, Oxypetalum globosum, from montane environments of northern Argentina, is described, illustrated, and compared to similar species. Data on its habitat, distribution, ecology, and phenology are provided. This is an outstanding species within Oxypetalum due to its flowers with maroon, globose corollas, with patent, rounded corolla lobes, and a bright pink, exserted, hemispheric stylar-head appendage, which suggest fly- pollination. The difficulties in delimiting genera of Oxypetalinae are discussed. A key to the species of Oxypetalum from northern Argentina is included. Fil: Martín, Claudia Melisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina Fil: Zanotti, Christian Alejandro. 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: Ezcurra, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

Premise of research. Although colleters are one of the most studied glands of the Apocynaceae, very little is known regarding the composition of their secretion. The aim of this study was to analyze histochemically vegetative and floral colleters of Asclepiadoideae (Apocynaceae) and verify their function during organ development.Methodology. Shoot apex, leaves, and flowers in different developmental stages were processed according to usual techniques in plant anatomy and submitted to histochemical tests.Pivotal results. Foliar and floral colleters of Peplonia secrete mucilage exclusively, while those of Asclepias, Blepharodon, Fischeria, Matelea, and Oxypetalum secrete mucilage, proteins, phenolic compounds, and lipids, including fatty acids. The secretion permeates and involves shoot apex, floral buds, and the developing organs, protecting these meristematic regions.Conclusions. The secretion of colleters of Peplonia is efficient in preventing the desiccation of organs but allows fungal proliferation amo...

Premise of research. Flowers of some Apocynaceae present an unusual synorganization among parts and organs, which has led to the origin of new organs and a type of pollen dispersal and pollination unique to eudicots. The synorganization of androecium and gynoecium allowed the evolution of the pollinarium, a very complex and species-specific structure composed of pollen grains (pollinium) and secretions produced by the style head (translator). The aim of this study was to investigate the structure and activity of the secretory system related to the morphogenesis of pollinaria and the composition of their secretions in flowers of Asclepiadeae.Methodology. Flowers and buds of Asclepias, Gonioanthela, Matelea, and Oxypetalum were fixed, embedded in Paraplast, and sectioned in a rotary microtome for analysis under light microscopy. SEM was performed for additional structural data, and histochemical tests were carried out to reveal the main chemical composition of the secretions involved in pollinaria morphogen...

In 2004, a damping-off symptom was found on southern star, Oxypetalum caeruleum, in Kochi Prefecture, Japan. Two Phytophthora strains with different colony patterns on potato dextrose agar were isolated, and their pathogenicity was confirmed by inoculation of southern star plants and their reisolation from symptomatic plants. Both fungi were identified as Phytophthora palmivora based on morphology, physiology, and sequence analysis of the internal transcribed spacers of nuclear ribosomal DNA. This is the first report of Phytophthora blight of southern star in the world.

El resultado de nuestros estudios (literatura, revisión de material) sobre el género Oxypetalum R. Br. en Paraguay, nos permite presentar una sinopsis de las 31 especies, 1 subespecie y 2 variedades aceptadas para este país. Publicamos aquí una combinación y un sinónimo nuevos así como cuatro lectotipificaciones. Se incluyen todos los nombres descritos en base a tipos colectados en Paraguay así como su tipificación completa. Sin embargo, no hemos citado material típico colectado fuera de Paraguay. Para la sinonimia general, se hace referencia a los trabajos recientes que la incluye. Se ha consultado todo el material del género existente en los siguientes herbarios: BAB, BACP, BM, CTES, FCQ, G, K, M, OXF, P, SI, V, W. En relación al material típico depositado en G, las fotografias digitales se pueden encontrar en nuestra base de datos (http :/ /www.ville-ge.ch/musinfo/bdlcjb/chg/search.php ). Los números que acompañan las citas de los especímenes en G corresponden a los códigos de barras presentes en cada espé- cimen registrado en nuestra base. Para otros herbarios, incluimos también los códigos de barras cuando lo hemos podido encontrar. La atribución de las autoridades de los nombres publicados en Plantae Hasslerianae (CHODAT, 1898-1902; CHODAT & HASSLER, 1902-1907) se realiza de acuerdo a las pautas indicadas en RAMELLA & PERRET (2003b). Fil: Fontella Pereira, J.. Universidade Federal do Rio de Janeiro; Brasil Fil: Caceres Moral, Sergio Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina Fil: Britto de Goes, M.. Universidade Federal do Rio de Janeiro; Brasil

RAMELLA, L. & P. PERRET (ed.) (2010). Notula ad Floram paraquaiensem, 106. Candollea 65: 393–402. In Spanish, French and English abstracts. Thirty-fifth installment of a series dedicated to the presentation of taxonomic, nomenclatural or floristic novelties in relation with the project “Flora del Paraguay” as well as complements to already published treatments. Organizational information and accounts on the advancement of the project are sometimes added by the editors. — Notula 106. Synopsis and typifications of the species of the genus Oxypetalum R. Br. (Asclepiadaceae) in Paraguay, by Jorge Fontella Pereira, Sergio A. Caceres Moral & Monique Britto de Goes. The authors present a key and a synopsis of the 31 species and 3 infraspecific taxa of the genus Oxypetalum R. Br. in Paraguay. They validate the new combination Oxypetalum martii var. nanum (Malme) Fontella & S. A. Caceres and publish a new synonym. The authors lectotypify: Oxypetalum acerosum Malme, Oxypetalum clavatum Malme, Oxypetalum ce...

In vitro propagation protocol for Lilium oxypetalum, a high altitude Himalayan endemic lily, has been developed. Effect of explant types (i.e., callus and in vitro bulblet scales) and sucrose concentration [0–6.0% (w/v)] on in vitro bulblet regeneration of L. oxypetalum was tested in previously optimized Murashige and Skoog basal medium supplemented with 2.0 μM 6-benzyladenine and 0.1 μM α-naphthaleneacetic acid. Callus explants produced significantly (P < 0.01) higher number of bulblets per explant than bulblet scale explants. Of the different concentrations of sucrose tested, 4.5% (w/v) sucrose showed significantly (P < 0.01) higher percentage regeneration (i.e., 70.8 ± 4.2 and 79.2 ± 4.2% regeneration on callus and bulblet scale explants, respectively), and produced higher number of bulblets per explant (i.e., 9.0 ± 0.4 and 5.4 ± 0.5 bulblets on callus and bulblet scale explants, respectively). Regenerated bulblets developed 2–3 leaves when subcultured for 4 weeks and were subsequently transferred ex vitro with a survival rate of 66.7% after 6 weeks. Leaves of the survived plantlets became dry after growing ex vitro for 10 weeks, amongst which 86.4% re-sprouted after remaining dormant for 5–6 weeks and produced 1.5 bulblets per explant. Findings of the present study hold promise for efficiently multiplying the target species in view of its potential economic and conservation significance.

O presente trabalho apresenta a nova ocorrência de Oxypetalum aurantiacum Malme ex Chod. & Hassl. (Apocynaceae, Asclepiadoideae) para o Brasil, no estado do Paraná. A espécie é descrita e ilustrada e são feitos comentários sobre a sua distribuição geográfica e o seu habitat. Oxypetalum uruguayense Malme e Oxypetalum arachnanthum Arechav. são propostos como novos sinônimos.

Floral volatiles of 15 plant species from 8 genera ( Cynanchum , Funastrum , Gonolobus , Metastelma , Oxypetalum , Orthosia , Sarcostemma , and Vincetoxicum ) of the Apocynaceae-Asclepiadoideae tribe Asclepiadeae were investigated to get a better understanding of the odor chemistry, and of the role of odors in pollinator attraction. Floral volatiles were collected via headspace adsorption and analysed by GC–MS (gas chromatography–mass spectrometry). Of the 170 volatile compounds detected, 128 were identified, most of which are widespread floral scent compounds known from many different plant species. The species can be divided into two main groups: (1) species dominated by monoterpenoids (linalool, Z / E -ocimene), and (2) species dominated by benzenoids (benzaldehyde, phenylacetaldehyde, 2-phenylethyl acetate). Species of both chemotypes are pollinated mainly by Hymenoptera and Lepidoptera, and possibly these insects are effectively attracted by both monoterpenoids and benzenoids; alternatively, benzenoid-dominated plant species might attract a different subset of pollinators than the monoterpenoid-dominated plants.

This paper studies phenology and pollination ecology of an assemblage of nine small-flowered species of Asclepiadoideae–Asclepiadeae in a southern Ecuadorian mountain forest. These observations were augmented by laboratory studies of floral traits including scanning electron microscopy. Supported by multidimensional scaling analysis, three distinct pollination systems were identified: (a) pollination by small flies (Orthosia, Scyphostelma), (b) pollination by small bees and flies (Ditassa), and (c) pollination unspecialized (“Cynanchum”, Jobinia, Oxypetalum). Although numerous floral visitors were observed in the field, pollinaria were carried by only seven insect species. The average pollinaria removal rate of all species was low with 0.32±0.13%, and still lower for the pollinia insertion rate with 0.13±0.07%. The ratio of inserted pollinia to removed pollinaria was comparatively high with an average of 42.7±22.3%. If an insect achieved pollinia transfer, it did so very effectively. The complex floral morphology of the Asclepiadoideae has often been interpreted as a general trend toward specialization, but our observations indicate that the flowers are specialized functionally rather than ecologically.

Most genera of the subfamily Asclepiadoideae (i.e., 29 genera) can be found in the southeastern Brazilian region. Among these, the most representative is Oxypetalum R. Br., with 71 taxa (including specific and infraspecific). In Rio de Janeiro State, there are 25 taxa of Oxypetalum that are climbers, with the exception of O. patulum E. Fourn., which is a suberect shrub and decumbent. Most taxa from Rio de Janeiro occur in secondary Atlantic Forest, but four are from sandy coastal plain (restinga) vegetation, namely O. alpinum (Vell.) Fontella & E. A. Schwarz var. alpinum, O. pachyglossum Decne., O. banksii Schult. subsp. banksii, and O. banksii subsp. corymbiferum (E. Fourn.) Fontella & C. Valente. The latter species is restricted to restingas. Some taxa occur in high-altitude grasslands, namely O. costae Occhioni, O. lanatum Decne ex E. Fourn., O. patulum E. Fourn., O. sublanatum Malme, O. insigne (Decne.) Malme var. insigne, O. insigne var. glabrum (Decne.) Fontella & E. A. Schwarz, O. insigne ...

Sobre la base de ejemplares recolectados en Misiones, Argentina, se describe una nueva especie del género Oxypetalum (Apocynaceae: Asclepiadoideae) afín a O. argentinum, O. humile y O. microphyllum. Las poblaciones hasta ahora conocidas se localizan en fragmentos de pastizales rodeados de selva subtropical. Fil: Keller, Hector Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina

Oxypetalum gyrophyllum Farinaccio & Mello-Silva and O. oblanceolatum Farinaccio & Mello-Silva, two new species of Asclepiadoideae (Apocynaceae) from Brazil, are described and illustrated. Both species may be included in the O. insigne (Decaisne) Malme group. Oxypetalum gyrophyllum is closely related to O. glabrum (Decaisne) Malme, differing mainly by bigger and more circular leaves, a smaller corpusculum, and smaller teeth, which are curved inward and included versus curved outward and free. Oxypetalum oblanceolatum is immediately distinguished from all species of this group by oblanceolate leaves, an uncommon character state in the genus. A key for the species of the Oxypetalum insigne group is provided.

Analysis of the trnT-trnL spacer, the trnL intron, the trnL-trnF spacer, and the rps16 intron of 106 species in 34 of the 45 genera of New World Asclepiadeae in the former subtribes Metastelmatinae, Oxypetalinae, and Gonolobinae shows that these genera form a well-supported clade (“MOG”). The small Andean genus Pentacyphus is sister to the remaining MOG clade. The former Gonolobinae form a well-supported subclade closely related to members of Tassadia, Funastrum, and former Oxypetalinae. The only genera that are monophyletic as presently circumscribed are Tassadia and Funastrum. The separation of Tweedia from Oxypetalum is justified by our results. Philibertia is monophyletic only if Amblystigma, Fontellaea, Melinia, Mitostigma, and Podandra are also included. Most species of Blepharodon and Hemipogon are not monophyletic with the respective type species. Some former Astephanus and Cynanchum species as well as the monotypic Grisebachiella are imbedded in Diplolepis (D. descolei, D. geminiflora, D...

The floral morphology of seven Oxypetalum species and, in particular, the spatial relationship between the five stigmatic chambers and two separate ovaries of their flowers with respect to transmission of the pollen tube are studied. In all species, except O. banksii subsp. banksii, floral morphology is similar to that in other Asclepiadeae, and the flowers pollinated with one pollinium develop only one follicle, which means compitum absence. In O. banksii subsp. banksii flowers, the secretory interstaminal tissue lines the inner walls of the stigmatic chambers as in the other species studied, but it also reaches the upper part of the inner surface of the filament tube, where it surrounds the styles, an unprecedented feature for Asclepiadaceae. This tissue secretes nectar and mucilage; the latter acts as transmitting medium for the growth of pollen tubes from pollinia inserted and hydrated in stigmatic chambers (“hyperstigmas”). Mucilage also functions as an extragynoecial compitum: in flowers pollinated with one pollinium both carpels develop into a follicle.

Climbers are considered heliophytes. They are copious at the margins of forests and natural and man-made clearings. The objective of this paper was to study the initial growth of seedlings maintained under full sunlight and shaded conditions (under a vegetation canopy). The species studied were: Aristolochia galeata, Arrabidea triplinervia, Bidens brasiliensis, Canavalia parviflora, Chamissoa altissima, Cissus sicyoides, Dalechampia pentaphylla, Dicella bracteosa, Dioscorea sp., Gouania virgata, Mascagnia anisopetala, Mutisia coccinea, Oxypetalum molle, Pithecoctenium crucigerum, Rynchosia phaseoloides, Serjania multiflora and Solanum flaccidum. The initial growth of the seedlings was followed under two conditions: at the margin and under the canopy of a mesophyllous tropical forest (22° 49′55′′ S–47° 06′33′′ W). The climbers showed high rates of growth in sunlight when compared to those under canopy. Most of the species presented higher growth of the shoot than roots but in general no significative differences between root/shoot were found in both treatments. Bidens, Cissus, Mutisia and Pithecoctenium showed a very high mortality rate under canopy but, most of the studied species survived under deep shaded forest for approximately 100 days.

Including the results reported in this paper, there are 41 species of Oxypetalum (Apocynaceae, Asclepiadoideae) that occur in Argentina, eight of them endemic: O. arenicola, O. fontellae, O. gracile, O. lynchianum, O. longipedunculatum, O. pubescens, O. tucumanense and O. teyucuarense. The last is a new species from the Paraje Teyú Cuaré, San Ignacio, Misiones Province, Argentina, which is described and illustrated here. It shares some morphological features with O. jorgensenii, but, overall, it does not closely resemble any other species of the genus morphologically in its unique assemblage of characteristics. In addition to this new species, we here report two additional species for the first time in Argentina Fil: Keller, Hector Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina Fil: Farinaccio, Maria Ana. Universidade Federal Do Mato Grosso Do Sul; Brasil

We postulates the phylogenetic relationships of section Sinomartagon using 64 Lilium taxa and two related taxa based on nucleotide sequence variations in the internal transcribed spacer regions of nuclear ribosomal DNA. Excluding the 5.8S unit, a total of 479bp were analyzed by three methods, i.e. maximum likelihood, maximum parsimony and neighbor-joining. Sinomartagon was polyphyletic and divided into five groups: (1) L. henryi, (2) L. henricii, L. macklinae, L. oxypetalum and L. nanum, (3) L. nepalense, (4) L. duchartrei, L. lankongense, L. amoenum, L. wardii and L. taliense, and (5) 10 other taxa of subsections 5a and 5b. This classification did not correspond to the subsections defined by Comber (1949), and all the groups should be recognized as distinct taxa. The second group which included mainly Nomocharis-like Lilium, should be treated as a different taxon such as section Lophophorum. Since the last group with section Dauricum and L. bulbiferum included L. davidii, the type of Sinomartagon, they could be considered to correspond to the true section Sinomartagon. The results provide a more convincing phylogenetic position for Sinomartagon.

Matelea ganglions (Vell.) Rapini and Oxypetalum harleyi (Fontella & Goyder) Farinaccio are proposed to make the combinations available at the level of species for the forthcoming survey of Apocynaceae from Morro do Chapeu, Bahia, Brazil.

Oxypetalum lividum (Apocynaceae, Asclepiadoideae), a new species from the Department of San Martin, Peru, is here described and illustrated. Oxypetalum lividum is similar to O. weberbaueri , but it differs by its sessile, 1 – 5-florous inflorescences, pedicels 0.7 – 3.5 mm long, and flowers 9 – 11 mm long, which are borne on short pedicels 0.7 – 3.5 mm long; whereas O. weberbaueri has pedunculate, 10 – 20-florous inflorescences, pedicels 5 – 7 mm long, and flowers ca. 20 mm long. The bluish-green leaves of O. lividum may also distinguish it from all other species of the genus.

We present a synopsis of Oxypetalum (Asclepiadoideae, Apocynaceae) in Bolivia. In addition, one new species, Oxypetalum urceolatum , is described, illustrated, and compared to its putative closest relatives. Oxypetalum urceolatum forms a complex with O. erianthum, O. brachystemma, O. dactylostelma , O. dombeyanum , O. molle, O. pearsonii , and O. fuscum . Morphologically, O. urceolatum appears most closely related to O. dactylostelma , from which it differs in having a conical, rather than expanded, style-head appendage and a glabrous, not pilose, throat to the corolla. In addition to this new species, we present a key to species of Oxypetalum in Bolivia.

Floret senescence of Oxypetalum caeruleum was investigated in relation to ethylene production and its sensitivity to ethylene. Ethylene production increased as the florets senesced, and conversely, their senescence was accelerated by exogenous application of ethylene at 2 or 10 μl·liter-1 for 24 hr, indicating that Oxypetalum florets are sensitive to the gaseous hormone. Treatment with silver thiosulphate complex (STS), an ethylene action inhibitor, extended the vase life of florets. Thus, ethylene is considered to be involved in the senescence of cut Oxypetalum florets.

Oxypetalum sylvestre (Hook. & Arn.) Goyder & Rapini, comb. nov. Basionym: Schistogyne sylvestris Hooker & Arnott (1834: 292). Type: “Banda Orientale”, no date, J . Baird s.n. (lectotype (here designated) K!). Paratypes: ARGENTINA. Entre Rios: no locality, no date, J . Tweedie 219 (K!). URUGUAY. Without locality, no date, J . Tweedie s.n. (K!)., Published as part of Rapini, Alessandro, Pereira, Jorge Fontella & Goyder, David J., 2011, Towards a stable generic circumscription in Oxypetalinae (Apocynaceae), pp. 9-16 in Phytotaxa 26 on page 13, DOI: 10.11646/phytotaxa.26.1.2, http://zenodo.org/record/4894142, {"references":["Hooker, W. J. & Arnott, G. A. W. (1834) Contributions towards a flora of South America and the islands of the Pacific. 1. Extra-tropical South America. Journal of Botany, being a second series of the Botanical Miscellany 1: 276 - 296"]}

Oxypetalum Brown (1810: 30), nom. cons. Type: O. banksii Schultes (1820: 91). Gothofreda Ventenat (1808: t. 60), nom. rej. Schistogyne Hooker & Arnott (1834: 291). Type: S. sylvestris Hooker & Arnott (1834: 292). Synon. nov. Calostigma Decaisne (1838: 343). Type: C. insigne Decaisne (1838: 344; t. 12, f. H). Schizostemma Decaisne (1838: 344). Type: non designatus. Pachyglossum Decaisne (1838: 345). Type: non designatus. Bustelma Fournier (1885: 287). Type: B. warmingii Fournier (1885: 287). Dactylostelma Schlechter (1895: 452). Type: D. boliviense Schlechter (1895: 452). Corollonema Schlechter (1914: 441). Type: C. boliviensis Schlechter (1914: 441). Amblyopetalum Malme (1927: 2). Type: A. coccineum (Grisebach 1874: 206) Malme (1937: 8). Metoxypetalum Morillo (1994: 145). Type: M. retusum (Markgraf 1933: 787) Morillo (1994: 146). Note:— Oxypetalum is the largest genus of Oxypetalinae, including around 120 species, distributed from Argentina to Mexico, with the centre of diversity in central-eastern South America. Most species are characterised by a combination of flowers with lanceolate corolla lobes, corona lobes gynostegial in origin but displaced onto the base of the corolla, free above and adaxially ornamented, style-head forming a rostrate appendage at the apex of gynostegium simulating a stigma, and caudicles of pollinaria with lateral teeth. Schistogyne was created based on the unusual appendage of the style-head with seven linear lobes in S. sylvestris: ‘ Stygma sub-7-partitum (!), segmentis subulato-filiformis.’ (Hooker & Arnott 1834: 292), and with gynostegial corona lobes in a staminal position. Variations of the style-head appendage were used to recognise some genera currently considered synonym of Oxypetalum (e.g., Calostigma). Nevertheless, this is a polymorphic structure and variations are found even in closely related species. For instance, O. pilosum Gardner (1842: 539) exhibits style-head terminating in a rostrate appendage, whereas O. erostre Fournier (1885: 265), which is the closest species and was eventually considered synonym of the former (Valente et al. 1973), exhibit a conical style-head lacking an appendage. Besides confirming the inclusion of Amblyopetalum, Bustelma and Dactylostelma in the synonymy of Oxypetalum, phylogenetic studies of plastid regions (Rapini et al. 2003, Liede-Schumann et al. 2005) also showed Schistogyne nested in core Oxypetalum, closely related to O. banksii. To become monophyletic, Oxypetalum must include Schistogyne. Below, we provide the combinations for the eight accepted species of Schistogyne in Oxypetalum, designate lectotypes for three species and indicate a new synonym., Published as part of Rapini, Alessandro, Pereira, Jorge Fontella & Goyder, David J., 2011, Towards a stable generic circumscription in Oxypetalinae (Apocynaceae), pp. 9-16 in Phytotaxa 26 on page 12, DOI: 10.11646/phytotaxa.26.1.2, http://zenodo.org/record/4894142, {"references":["Brown, R. (1810) On the Asclepiadeae, a Natural Order of Plants Separated from the Apocineae of Jussieu. London. (Preprinted from Memoirs of the Wernerian Natural History Society 1: 12 - 78 (1811 )).","Schultes, J. A. (1820) Systema vegetabilium: Secundum Classes, Ordines, Genera, Species. Cum Characteribus Differentiis et Synonymis. Editio Nova, Speciebus Inde ab Editione XV. Detectis aucta et Locupletata, vol. 6. J. G. Cotta, Stuttgart, 857 pp.","Ventenat, E. P. (1808) Choix de Plantes, dont la Plupart sont Cultivees dans le Jardin de Cels, part 10. Imprimerie de Crapelet, Paris, t. 55 - 60.","Hooker, W. J. & Arnott, G. A. W. (1834) Contributions towards a flora of South America and the islands of the Pacific. 1. Extra-tropical South America. Journal of Botany, being a second series of the Botanical Miscellany 1: 276 - 296","Decaisne, J. (1838) Etudes sur quelques genres et especes de la famille des Asclepiadees. Annales des Sciences Naturelles; Botanique, serie 2, 9: 257 - 278; 321 - 348; t. 9 - 12.","Fournier, E. (1885) Asclepiadaceae. In: Martius, C. F. P. & Eichler, A. W. (eds.), Flora Brasiliensis, vol. 6, part 4. Lindauer, Munchen, pp. 189 - 332, t. 50 - 98.","Schlechter, R. (1895) Asclepiadaceae Kuntzeanae. Oesterreichische Botanische Zeitschrift 45: 449 - 454.","Schlechter, R. (1914) Asclepiadaceae novae bolivienses Herzogianae. Repertorium Specierum Novarum Regni Vegetabilis 13: 438 - 443.","Malme, G. O. A. (1927) Asclepiadaceae Duseninanae in Parana collectae. Arkiv for Botanik utgivet av Kongliga Svenska Vetenskapsakademien 21 A (3): 1 - 48; t. 1 - 4.","Grisebach, A. (1874) Plantae Lorentzianae. Abhandlungen der Koniglichen Gesellschaft der Wissenschaften zu Gottingen 19: 49 - 280.","Malme, G. O. A. (1937) Einige Beitrage zur Kenntnis sudamerikanischer Asklepiadazeen. Arkiv for Botanik utgivet av Kongliga Svenska Vetenskapsakademien 29 A (4): 1 - 9.","Morillo, G. (1994) Metoxypetalum Morillo, gen. nov. y especies nuevas o interesantes en Ditassa R. Br. y Macroscepis H. B. K. Ernstia 3: 143 - 150.","Markgraf, F. (1933) Asclepidaceae. In: Pilger, R. (ed.), Neue Arten aus tropischen Amerika. Notizblatt des Botanischen Gartens und Museums zu Berlin-Dahlem 11: 787 - 789.","Gardner, G. (1842) Contributions towards a Flora of Brazil. London Journal of Botany 1: 528 - 548.","Valente, M., Fontella-Pereira, J. & Alencastro, F. M. M. R. (1973) Contribuicao ao estudo das Asclepiadaceae brasileiras, IX. Estudos taxonomico e anatomico de Oxypetalum appendiculatum Mart., Oxypetalum pilosum Gardn. e Oxypetalum sublanatum Malme. Anais da Academia Brasileira de Ciencias 45: 121 - 149.","Rapini, A., Chase, M. W., Goyder, D. J. & Griffiths, J. (2003) Asclepiadeae classification: evaluating the phylogenetic relationships of New World Asclepiadoideae (Apocynaceae). Taxon 52: 33 - 50.","Liede-Schumann, S., Rapini, A., Goyder, D. J. & Chase, M. W. (2005) Phylogenetics of the New World subtribes of Asclepiadeae (Apocynaceae - Asclepiadoideae): Metastelmatinae, Oxypetalinae, and Gonolobinae. Systematic Botany 30: 183 - 194."]}

Oxypetalum pentasetum (Rusby) Goyder & Rapini, comb. nov. Basionym: Schistogyne pentaseta Rusby (1920: 98). Type: BOLIVIA. La Paz: Yungas, no date, M . Bang s.n. (holotype NY!). = Schistogyne mandonii Malme (1933: 12; f. 1e, 2b). Type: BOLIVIA. Larecaja: near Sorata mountain, Cerro Iminapi, February–April 1859, G. Mandon 358 (holotype S!, isotypes BM!, F!, K!, P!, W!). Synon. nov., Published as part of Rapini, Alessandro, Pereira, Jorge Fontella & Goyder, David J., 2011, Towards a stable generic circumscription in Oxypetalinae (Apocynaceae), pp. 9-16 in Phytotaxa 26 on page 13, DOI: 10.11646/phytotaxa.26.1.2, http://zenodo.org/record/4894142, {"references":["Rusby, H. H. (1920) Asclepiadaceae. In: Descriptions of Three Hundred New Species of South American Plants. Henry Hurd Rusby, New York, pp. 92 - 102.","Malme, G. O. A. (1933) Die gattung Schistogyne Hook. et Arn. Arkiv for Botanik utgivet av Kongliga Svenska Vetenskapsakademien 25 A (14): 1 - 15."]}

Oxypetalum heptalobum Goyder & Rapini, nom. nov. Basionym: Schistogyne boliviensis Schlechter (1914: 442), [non Oxypetalum boliviense Schlechter (1906: 602)]. Type: BOLIVIA. “Windend im Gebüsch an der Waldgrenze bei Tres Cruces”, February 1911, T. Herzog 1630 (lectotype (here designated) L!, duplicate F!]. Note:—The lectotype is designated here because the holotype at B was destroyed. Etymology:—The 7-lobed appendage of the gynostegium was used to recognise Schistogyne; however, this is the only Bolivian species that presents this characteristic, which is why we chose this epithet., Published as part of Rapini, Alessandro, Pereira, Jorge Fontella & Goyder, David J., 2011, Towards a stable generic circumscription in Oxypetalinae (Apocynaceae), pp. 9-16 in Phytotaxa 26 on page 12, DOI: 10.11646/phytotaxa.26.1.2, http://zenodo.org/record/4894142, {"references":["Schlechter, R. (1914) Asclepiadaceae novae bolivienses Herzogianae. Repertorium Specierum Novarum Regni Vegetabilis 13: 438 - 443.","Schlechter, R. (1906) Asclepiadaceae andinae. In: Plantae novae andinae imprimis Weberbauerianae - II. Botanische Jahrbucher fur Systematik, Pflanzengeschichte und Pflanzengeographie 37: 601 - 627."]}

Oxypetalum pubescens (Malme) Goyder & Rapini, comb. nov. Basionym: Schistogyne pubescens Malme (1933: 10; f. 1d, 2d). Type: ARGENTINA. Catamarca: Sierra de la Huerte, F . Schickendantz s.n. (holotype S!)., Published as part of Rapini, Alessandro, Pereira, Jorge Fontella & Goyder, David J., 2011, Towards a stable generic circumscription in Oxypetalinae (Apocynaceae), pp. 9-16 in Phytotaxa 26 on page 13, DOI: 10.11646/phytotaxa.26.1.2, http://zenodo.org/record/4894142, {"references":["Malme, G. O. A. (1933) Die gattung Schistogyne Hook. et Arn. Arkiv for Botanik utgivet av Kongliga Svenska Vetenskapsakademien 25 A (14): 1 - 15."]}

Oxypetalum tucumanense (T.Mey.) Goyder & Rapini, comb. nov. Basionym: Schistogyne tucumanensis Meyer (1941: 278; t. 1). Type: ARGENTINA. Tucumán: Famaillá, Villa Nougués, 27 November 1921, S . Venturi 1576 (holotype LIL!, isotypes MO!, SI!)., Published as part of Rapini, Alessandro, Pereira, Jorge Fontella & Goyder, David J., 2011, Towards a stable generic circumscription in Oxypetalinae (Apocynaceae), pp. 9-16 in Phytotaxa 26 on page 13, DOI: 10.11646/phytotaxa.26.1.2, http://zenodo.org/record/4894142, {"references":["Meyer, T. (1941) Asclepiadaceae argentinensis novae aut criticae. Lilloa 6: 277 - 283; t. 1 - 3."]}

Oxypetalum fiebrigii (Malme) Goyder & Rapini, comb. nov. Basionym: Schistogyne fiebrigii Malme (1933: 14; f. 1a). Type: BOLIVIA. Tarija: San Luis, 24 January 1904, K. Fiebrig 2669 (holotype S!, isotypes B destroyed, BM!, K!, US!)., Published as part of Rapini, Alessandro, Pereira, Jorge Fontella & Goyder, David J., 2011, Towards a stable generic circumscription in Oxypetalinae (Apocynaceae), pp. 9-16 in Phytotaxa 26 on page 12, DOI: 10.11646/phytotaxa.26.1.2, http://zenodo.org/record/4894142, {"references":["Malme, G. O. A. (1933) Die gattung Schistogyne Hook. et Arn. Arkiv for Botanik utgivet av Kongliga Svenska Vetenskapsakademien 25 A (14): 1 - 15."]}

Oxypetalum karstenianum Goyder & Rapini, nom. nov. Basionym: Schistogyne decaisneana Karsten (1866: 121), (non Oxypetalum decaisneanum Meyer 1951: 361). Type: BRAZIL. Rio Grande do Sul: no locality, no date, A . Isabelle s.n. (holotype P!). Etymology:—The new name of this species honours C. W. Herman Karsten who recognised it as distinct from the rest of the material identified by Decaisne (1844) as Schistogyne sylvestris., Published as part of Rapini, Alessandro, Pereira, Jorge Fontella & Goyder, David J., 2011, Towards a stable generic circumscription in Oxypetalinae (Apocynaceae), pp. 9-16 in Phytotaxa 26 on page 13, DOI: 10.11646/phytotaxa.26.1.2, http://zenodo.org/record/4894142, {"references":["Karsten, G. K. W. H. (1866) Florae Columbiae Terraumque Adjacentium Specimina Selecta in Peregrinatione Duodecim Annorum Observata Delineavit et Descripsit, vol. 2, part 4. Ferdinand Duemmler Successores, Berlin, pp. 115 - 154, t. 161 - 180.","Meyer, T. (1951) Notas sobre Asclepiadaceas sudamericanas, I. Duseniana 2: 365 - 368.","Decaisne, J. (1844) Asclepiadaceae. In: Candolle, A. L. P. P. (ed.), Prodromus Systematis Naturalis Regni Vegetabilis, vol. 8. Treuttel & Wurtz, Paris, pp. 490 - 665."]}

Oxypetalum longipedunculatum (Malme) Goyder & Rapini, comb. nov. Basionym: Schistogyne longipedunculata Malme (1933: 11; f. 1c, 2c). Type: ARGENTINA. Salta: Candelaria, Cerro del Chorrillo, 27 April 1925, S. Venturi 3780 (Lectotype (here designated) S!, duplicates LIL!, MO!, SI!, US!). Paratype: ARGENTINA. Tucuman: Parque Centenario, 15 January 1928, S. Venturi 5733 (MO!, S!)., Published as part of Rapini, Alessandro, Pereira, Jorge Fontella & Goyder, David J., 2011, Towards a stable generic circumscription in Oxypetalinae (Apocynaceae), pp. 9-16 in Phytotaxa 26 on page 13, DOI: 10.11646/phytotaxa.26.1.2, http://zenodo.org/record/4894142, {"references":["Malme, G. O. A. (1933) Die gattung Schistogyne Hook. et Arn. Arkiv for Botanik utgivet av Kongliga Svenska Vetenskapsakademien 25 A (14): 1 - 15."]}

A new species of Oxypetalum , O. laciniatum Rapini & Farinaccio, is described and illustrated. It was collectedonly once in the moist forest of southern Bahia, and belongs to the O. cordifolium (Vent.) Schltr. speciescomplex. The new species, however, can be promptly distinguished from the others in this group by theflowers with longer lacinia (ca. 2.85 cm long), shorter pollinia (up to 0.3 mm long; about 1/3 of thecorpusculum length), and appendix of gynostegium with apex slightly bifid in subparallel branches.Key words : Asclepiadaceae, Atlantic forest, floristics, taxonomy. Introducao Oxypetalum R. Br. (Apocynaceae) e umgenero neotropical com cerca de 120 especies,ocorrendo da Argentina ao Mexico, mas comcentro de diversidade na porcao centro-leste daAmerica do Sul (Farinaccio 2006). A maioria dasespecies possui flores vistosas, geralmente comginostegio rostrado, simulando um estigma, epolinarios com caudiculos horizontais providosde um dente incluso. As especies brasileiras foramrevisadas por Hoehne (1916) e as argentinas porMeyer (1943); desde entao, varios estudos temcontribuido para a taxonomia do genero, comdestaque para floras estaduais recentes nasRegioes Sul e Sudeste do Brasil (

Incremental increases in temperature from 14 to 22 to 30C resulted in linear increases in stem length and node number and decreases in stem diameter and stem strength of Oxypetalum caeruleum (D. Don.) Decne. Higher temperatures also resulted in additional flower abortion, reduced time to flowering, and fewer flowering stems per inflorescence. Reduction in the photosynthetic photon flux (PPF) from 695 to 315 µmol·s -l ·m -2 had similar effects as increasing the temperature on vegetative characteristics, but had little effect on reproductive ones. The rate of stem elongation was greatest at low PPF for all temperatures and at high temperature for all PPF treatments. Net photosynthesis rose between 14 and 22C and declined at 30C for all PPF treatments. Long photoperiods (12 or 14 hours) resulted in longer internodes, longer stems, and more flowers per cyme than short photoperiods (8 or 10 hours), but photoperiod had little effect on flowering time. Treatments to reduce latex coagulant and silver thiosulfate treatments had no significant effect on vase life. Oxypetalum caeruleum (tweedia) belongs to Asclepiadacea e and bears light-green opposite leaves and cymose panicles, each cyme consisting of three to five five-petaled light-blue flowers. The species is native to Brazil and Uruguay (Bailey, 1951) and grown in the United. States, Holland, New Zealand, and Aus- tralia as a specialty cut flower crop. Other important ornamental crops in Asclepiadaceae are Asclepias tuberosa L., Stephanotis floribunda Brongn., and Hoya carnosa R. Br. Asclepias is day- neutral with respect to flowering, but long days promote shoot extension and leaf production (Lyons, 1985) and inhibit lateral branching (Lyons and Booze, 1983). Stephanotis is a long-day

Three small South American genera of Apocynaceae-Asclepiadoideae are included in a phylogeny of South American Apocynaceae-Asclepiadoideae using the trnT – L and trnL – F intergenic spacers and the trnL and rps16 introns. Two genera, Widgrenia and Rhyssostelma , are nested in the large genus Oxypetalum . One, Stenomeria , is congeneric with Tassadia . The correspondent and necessary new combinations, Oxypetalum nigricans and O. corymbosum , and Tassadia decalepis, T. fosteri and T. pentalepis are made. The new combination Tassadia guanchezii is proposed for a hitherto insufficiently known species of white sand savannas of Colombia and Venezuela. Lorostelma struthianthus , a synonym of Tassadia decalepis , is lectotypified. This manuscript proposes taxonomic changes that reflect advances in Oxypetalinae and Tassadiinae, and it emends the description of Tassadia guanchezii .

São reportados resultados de polinização aberta (flores expostas aos polinizadores), em indivíduos de O. mexiae de população natural, e de polinizações manuais (polinização cruzada e autopolinização), em indivíduos cultivados. Essa espécie ocorre na Reserva Florestal Mata do Paraíso, fragmento de floresta com cerca de 195ha e cuja vegetação original faz parte da unidade fitogeográfica de Floresta Atlântica. O. mexiae é trepadeira de grandes dimensões, que cresce na borda da mata, acompanhando curso d'água. É espécie autocompatível, mas autopolinização espontânea não ocorre por razões morfológicas. Sementes de frutos resultantes da xenogamia (40%) e autogamia (50%) apresentaram alta viabilidade (respectivamente, 99 e 100%). A frutificação, em população natural, foi nula, indicando que essa espécie apresenta limitação reprodutiva. Essa limitação é imposta pelo baixo nível de polinização, que restringe o número de frutos produzidos, e pela herbivoria, que impede que os frutos em desenvolvimento alcancem a maturidade. O baixo nível de polinização pode estar relacionado à fragmentação do hábitat. Além disso, há limitação na distribuição e abundância de O. mexiae imposta pelo hábitat. Results of open-pollination (exposed flowers), in natural population, and cross and self-pollination, in cultivated individuals, are reported in O. mexiae. This species occurs at the Reserva Florestal Mata do Paraíso, a forest fragment with 195ha, whose original vegetation is part of the phytogeographic unit of the Atlantic forest. O. mexiae is a climbing species of great dimension, which grows at the wood border, following the water flow. It is self-compatible, but spontaneous self-pollination does not occur for morphological reasons. Seeds of xenogamous (40%) and autogamous (50%) fruit sets presented a high viability (respectively, 99 and 100%). No fruit was produced in natural population, indicating that this species presents reproductive limitation. This limitation is imposed by a low level of pollination, which restricts the number of fruit-set, and herbivory, which impedes the developing fruits to reach maturation. The low level of pollination may be related to habitat fragmentation. Besides, O. mexiae habitat may further limit its distribution and abundance.

As estruturas secretoras foliares conhecidas como coleteres sao investigadas preliminarmente quanto ao seu potencial como caracteres taxonomicos para a elucidacao de problemas relativos ao genero Oxypetalum R.Br. (Asclepiadoideae, Apocynaceae) no Estado do Parana, Brasil. ABSTRACT The leaf secretory structures known as colleters were investigated in order to test their potential use as taxonomic characters to elucidate problems related to the genus Oxypetalum R.Br. (Asclepiadoideae, Apocynaceae) in State of Parana, Brazil. RESUME Les structures secretoires de la feuille connues comme“colleteres” ont ete recherchees pour tester leur usage potential comme caractere taxonomique pour elucider problemes relatives au genre Oxypetalum R.Br. (Asclepiadoideae, Apocynaceae) dans L'Etat du Parana, Bresil.

The floral morphology of seven Oxypetalum species and, in particular, the spatial relationship between the five stigmatic chambers and two separate ovaries of their flowers with respect to transmission of the pollen tube are studied. In all species, except O. banksii subsp. banksii, floral morphology is similar to that in other Asclepiadeae, and the flowers pollinated with one pollinium develop only one follicle, which means compitum absence. In O. banksii subsp. banksii flowers, the secretory interstaminal tissue lines the inner walls of the stigmatic chambers as in the other species studied, but it also reaches the upper part of the inner surface of the filament tube, where it surrounds the styles, an unprecedented feature for Asclepiadaceae. This tissue secretes nectar and mucilage; the latter acts as transmitting medium for the growth of pollen tubes from pollinia inserted and hydrated in stigmatic chambers (“hyperstigmas”). Mucilage also functions as an extragynoecial compitum: in flowers pollinated with one pollinium both carpels develop into a follicle.

Pollinarium removal and pollinium insertion of seven Oxypetalum species (O. alpinum var. alpinum, O. appendiculatum, O. banksii subsp. banksii, O. jacobinae, O. mexiae, O. pachyglossum and O. subriparium) were recorded in Viçosa, Minas Gerais. They presented a tendency of one or two pollinarium removals and one pollinium insertion (single insertion), except O. appendiculatum. In this species, mainly, two pollinia of the same pollinarium were inserted per stigmatic chamber (double insertion), resulting exceptionally in 6-10 inserted pollinia in a flower, an unusual occurrence among the Asclepiadaceae. No association between removal and insertion was found, e.g., O. subriparium and O. banksii subsp. banksii had the highest pollinarium removal (1.78 and 1.45, respectively) and one of the lowest pollinium insertions (0.02 in both species), per flower. Oxypetalum mexiae showed the lowest pollinarium removal and pollinium insertion per flower (0.09 and 0.01, respectively) among the studied species and other Asclepiadaceae. Oxypetalum subriparium, O. banksii subsp. banksii and O. mexiae might be having reproductive limitations. Pollinarium removal and pollinium insertion per flower of the studied species varied from site to site, similarly to what was recorded for other Asclepiadaceae Se registró la remoción de polinarios y la inserción de polinios de siete especies de Oxypetalum (O. alpinum var. alpinum, O. appendiculatum, O. banksii subsp. banksii, O. jacobinae, O. mexiae, O. pachyglossum y O. subriparium) en Viçosa, Minas Gerais. Estas presentaron una tendencia de una o dos remociones de polinarios y una inserción de polinios (inserción única), excepto O. appendiculatum. En esta especie, principalmente, fueron insertados dos polinios del mismo polinario por cámara estigmática (inserción doble), resultando excepcionalmente en 6- 10 polinios insertados en una flor, una ocurrencia inusual en Asclepiadaceae. No se encontró asociación entre remoción en inserción, e.g., O. subriparium y O. banksii subsp. banksii tuvieron la remoción de polinarios más alta (1.78 y 1.45, respectivamente) y una de las inserciones de polinios más baja (0.02 en ambas especies), por flor. Oxypetalum mexiae mostró la remoción de polinarios y la inserción de polinios por flor más bajas (0.09 y 0.01, respectivamente) entre las especies estudiadas y otras Asclepiadaceae. Oxypetalum subriparium, O. banksii subsp. banksii y O. mexiae pueden estar teniendo limitaciones reproductivas. La remoción de polinarios y la inserción de polinios por flor de las especies estudiadas varió de sitio a sitio, similarmente a lo registrado para otras Asclepiadaceae.