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We present phylogenetic results for Justicieae, the largest of the major lineages of Acanthaceae. With 300% more sequence data and a similarly increased but also more geographically representative taxon sample compared to the only previous study of the lineage as a whole, we confirm the existence of the Pseuderanthemum Lineage, Isoglossinae, the Tetramerium Lineage and the Justicioid Lineage. To the last three lineages, we add a number of taxa with the goal of advancing our knowledge of genera (e.g., Isoglossa, Rhinacanthus) and of geographic areas (e.g., Malagasy and Asian Acanthaceae). These added taxa are accommodated within the phylogenetic framework for the lineages established in our earlier work with one exception. The monospecific genus Ichthyostoma is not placed in any of the established lineages but is instead sister to (Tetramerium Lineage + Justicioid Lineage). As this result is unexpected, we examined topologies both including and excluding this plant which revealed that other aspects of relationships remain stable whether Ichthyostoma is included or not. We point to Ichthyostoma as one of several Justicieae that will benefit from additional study. One species of Isoglossa is placed in the Tetramerium Lineage instead of with all other sampled members of the genus in Isoglossinae. Pollen morphology of I. variegata is more consistent with its phylogenetic placement here than with its taxonomic assignment to Isoglossa. As suggested in our earlier work, pollen morphology can be a powerful signal of phylogenetic relationships in Justicieae. With our increased sampling, we show that the Ptyssiglottis Lineage, a relatively small group of African and Asian plants, warrants recognition separate from Isoglossinae. With the addition of the Ptyssiglottis Lineage and excluding Ichthyostoma for now, the lineages of Justicieae are related as follows: (Pseuderanthemum Lineage ((Isoglossinae + Ptyssiglottis Lineage) (Tetramerium Lineage + Justicioid Lineage))). The Pseuderanthemum Lineage has been understudied to date and we here attempt to include representatives of all genera that are putatively part of this lineage and also to test monophyly of the larger genera. We identify a number of strongly supported clades but some aspects of relationship remain unresolved. Asystasia, Graptophyllum, Oplonia, and Pseuderanthemum are not monophyletic although, with a small number of nomenclatural changes, the first and second can be rendered monophyletic. With a range essentially as extensive as that of Justicieae as a whole, the Pseuderanthemum Lineage is biogeographically complex with patterns of distribution suggestive of multiple shifts between continents including Australia and parts of the Pacific basin. The calibrated phylogeny confirms that intercontinental shifts in distribution across Justicieae must have been by long-distance dispersal rather than by vicariance or stepwise dispersal over land bridges and also points to a number of groups that have potentially undergone rapid diversification. The Pseuderanthemum Lineage, in particular, requires considerable additional research to both understand relationships and achieve an informative taxonomy for the group. Although we here establish a phylogenetic framework across Justicieae, Next Generation Sequence data will be necessary to elucidate details of relationships in most lineages. Additional study of structural characters is also warranted as we continue to be unable to identify structural synapomorphies for a number of aspects of phylogenetic relationships that are very strongly supported by molecular data.

Summary DNA sequence data, macro-morphological evidence and pollen analysis are used to clarify the phylogenetic placement of two African species of Acanthaceae: Schaueria populifolia C.B.Clarke and Rhinacanthus ndorensis Schweinf. The combined data demonstrate that these species are only distantly related to the genera in which they are currently placed and provide strong support for recognition of new genera to accommodate them. Two new genera are therefore proposed and a taxonomic account is provided for each of these. The first, Champluviera I.Darbysh., T.F.Daniel & C.A.Kiel, is based primarily on S. populifolia but Chlamydocardia nuda C.B.Clarke (= Justicia tigrina Heine) is also included within this new genus based on shared morphological traits, at least one of which is synapomorphic and restricted to these species. Based on molecular evidence, Champluviera is placed in a well-supported clade of several genera that are together sister to the core Isoglossinae lineage of tribe Justicieae. The genus may be recognised morphologically by the combination of a dense spiciform terminal thyrse with the bracts, bracteoles and calyx lobes all slender and closely resembling one another; a bilabiate corolla lacking a rugula and with intricate speckling or striping on the lips; and, in particular, the putatively synapomorphic trait of anther thecae with broad, flattened, basal appendages that have an irregularly toothed fringe. The second new genus, Kenyacanthus I.Darbysh. & C.A.Kiel, is based on R. ndorensis and is so far thought to be monospecific. It is placed between core Diclipterinae and Monechma Group II within the expanded subtribe Diclipterinae in tribe Justicieae. Kenyacanthus can be recognised morphologically by having the combination of a trailing or procumbent habit; fasciculate inflorescences; bracts, bracteoles and calyces with hyaline margins; a bilabiate corolla with a slender cylindrical tube longer than the limb and with a shallow rugula; stenotribic flowers, with the stamens held against the lower lip; and anthers with only slightly offset thecae that lack appendages.

Premise of research. Plants with C4 photosynthesis are able to produce carbohydrates more efficiently than plants with C3 photosynthesis in warm climates when levels of atmospheric CO2 are reduced. The C4 pathway has evolved multiple times in distantly related lineages, but it is not known whether the same physiological transitions occurred in all lineages. Species with intermediate C3-C4 physiology and anatomy offer the opportunity to study how plants transition from C3 to C4. It is thus vital to characterize phylogenetic relationships and photosynthetic pathways in groups with C3-C4 intermediate species, as well as C3 and C4 species.Methodology. We assessed photosynthetic pathway evolution in the Afro-Asian genus Blepharis (Acanthaceae) by sampling 99 species for carbon isotope ratios, 18 species for leaf anatomy, and 36 species for phylogenetic analysis. We estimated when Blepharis clades diverged using a BEAST molecular dating analysis, and we estimated ancestral distributions using BioGeoBEARS. We al...

The Mirandea clade (Acanthaceae) is part of the Tetramerium lineage (Acanthaceae: Justicieae). Traditionally, macromorphological floral traits such as floral form and color have guided taxonomy in the Tetramerium lineage but earlier results on this group indicate that these traits are highly homoplastic. The present study includes all described species and multiple samples of Hoverdenia, Mirandea, and Yeatesia to fully delimit the Mirandea clade, test monophyly of species, and determine relationships among them using DNA sequence data from five regions (nuclear: nrITS and ncpGS; cp: trnS—G, ndhF—trnL(UAG), and trnT-L). The Mirandea clade is here shown to include seven species currently placed in four genera: Mirandea, Hoverdenia, Yeatesia, and Justicia. The lineage is edaphically and geographically cohesive, occurring along the Sierra Madre Oriental in Mexico and southern Texas in xeric habitats, except for one species that inhabits a broad geographical region of the southeastern U. S. A. in mesi...

More than a decade of phylogenetic research has yielded a well-sampled, strongly supported hypothesis of relationships within the large ( > 4000 species) plant family Acanthaceae. This hypothesis points to intriguing biogeographic patterns and asymmetries in sister clade diversity but, absent a time-calibrated estimate for this evolutionary history, these patterns have remained unexplored. Here, we reconstruct divergence times within Acanthaceae using fossils as calibration points and experimenting with both fossil selection and effects of invoking a maximum age prior related to the origin of Eudicots. Contrary to earlier reports of a paucity of fossils of Lamiales (an order of ∼ 23,000 species that includes Acanthaceae) and to the expectation that a largely herbaceous to soft-wooded and tropical lineage would have few fossils, we recovered 51 reports of fossil Acanthaceae. Rigorous evaluation of these for accurate identification, quality of age assessment and utility in dating yielded eight fossils judged to merit inclusion in analyses. With nearly 10 kb of DNA sequence data, we used two sets of fossils as constraints to reconstruct divergence times. We demonstrate differences in age estimates depending on fossil selection and that enforcement of maximum age priors substantially alters estimated clade ages, especially in analyses that utilize a smaller rather than larger set of fossils. Our results suggest that long-distance dispersal events explain present-day distributions better than do Gondwanan or northern land bridge hypotheses. This biogeographical conclusion is for the most part robust to alternative calibration schemes. Our data support a minimum of 13 Old World (OW) to New World (NW) dispersal events but, intriguingly, only one in the reverse direction. Eleven of these 13 were among Acanthaceae s.s., which comprises > 90% of species diversity in the family. Remarkably, if minimum age estimates approximate true history, these 11 events occurred within the last ∼ 20 myr even though Acanthaceae s.s is over 3 times as old. A simulation study confirmed that these dispersal events were significantly skewed toward the present and not simply a chance occurrence. Finally, we review reports of fossils that have been assigned to Acanthaceae that are substantially older than the lower Cretaceous estimate for Angiosperms as a whole (i.e., the general consensus that has resulted from several recent dating and fossil-based studies in plants). This is the first study to reconstruct divergence times among clades of Acanthaceae and sets the stage for comparative evolutionary research in this and related families that have until now been thought to have extremely poor fossil resources.

As part of our study of the Acanthaceae of Costa Rica and from a phylogenetic study of Ruellia as a whole, we place R. barbillana and R. metallica in synonymy with R. terminalis. We discuss species limits of R. terminalis and provide a key that distinguishes it from close relatives including R. grantii, R. oaxacana, and R. phyllocalyx. Ruellia puri is put into synonymy with R. jussieuoides, and R. standleyi is synonymized with R. ochroleuca. Disjunct distributions characterize R. terminalis, R. jussieuoides, and R. ochroleuca, although this pattern is most extreme in R. ochroleuca. Phylogenetic analysis of DNA sequence data lends support to our synonymy decisions. New lectotypifications are provided for Arrhostoxylum achimeniflorum, Dipteracanthus puri, Dipteracanthus puri β angustifolius, Dipteracanthus puri γ gymnocladus, Lychniothyrsus ochroleucus, and Otacanthus pearcei.

We took a two-tiered approach to test monophyly of Nelsonioideae and place the group within Lamiales, and to determine relationships among taxa within the group. Phylogenetic analysis of a molecula ...

Acanthaceae as circumscribed today consists of the three subfamilies Acanthoideae (Acanthaceae sensu stricto), Thunbergioideae and Nelsoniodieae, plus the genus Avicennia. Due to the morphological dissimilarities of Thunbergioideae and Nelsonioideae, the delimitation of the family has been controversial. The mangrove genus Avicennia was only recently associated with Acanthaceae for the first time, based on molecular evidence, but without morphological support. In this thesis, phylogenetic analyses of nuclear and chloroplast DNA sequences were used to test the monophyly and exact positions of Thunbergioideae and Nelsonioideae, and to infer detailed phylogenetic relationships within these subfamilies and among major lineages of Acanthaceae. Floral structure and development were comparatively studied in Avicennia and other Acanthaceae using scanning electron microscopy and stereo microscopy. Phylogenetic analyses strongly support monophyly of Thunbergioideae and Nelsonioideae, and place the latter clade with strong support as sister to all other plants treated as Acanthaceae. Thunbergioideae and Avicennia are moderately supported as sister taxa, and together they are sister to Acanthoideae. The general morphology of Avicennia can be easily accommodated in the Acanthaceae, and three synapomorphies support the suggested sister group relationship of Avicennia and Thunbergioideae: (1) collateral ovule arrangement, (2) vertical orientation of ovule curvature, and (3) an exposed nucellus that is contiguous with the ovary wall. Within Thunbergioideae and Nelsonioideae, support values for major lineages are generally high. With some exceptions, the constituent genera are supported as monophyletic. Evolutionary relationships among and within genera are discussed in a morphological and biogeographical context.

We used DNA sequence data from five genic regions (nrlTS; chloroplast trnL-F, trnT–L, rps16, trnS–G) to study phylogenetic relationships of the Tetramerium lineage (Acanthaceae: Justicieae). From a sample of 70 species (representing 25 genera) previously affiliated with the Tetramerium lineage, 68 are included therein. Our analyses excluded Papuasian Calycacanthus and Neotropical Streblacanthus monospermus from the Tetramerium lineage; however, two species described in Justicia (J. gonzalezii and J. medranoi) and a Malagasy species of uncertain generic affinities are nested within the lineage. A monophyletic Tetramerium lineage consists of 23 currently recognized genera with at least 168 species, more than 70% of which occur in the New World. Old World Chlamydocardia and Clinacanthus are serially sister to all other members of the lineage. Other Old World taxa consist of: Ecbolium clade (all sampled species of Ecbolium plus Malagasy Papulina richardii), Megalochlamys clade (Megalochlamys, Trichau...

We used DNA sequence data from four regions ([1] nrITS; the chloroplast [2] rps16 intron, [3] trnG-S spacer, and [4] trnL-F intron and spacer) to study phylogenetic relationships within tribe Acantheae (Acanthaceae). Our sample includes 18 of 20 recognized genera and 82 of ca. 500 species (plus two Justicieae as out-groups). Results of parsimony and Bayesian analyses were entirely congruent and provided strong support for monophyly of two sub-lineages of Acantheae, referred to here as the ‘one-lipped corolla’ and ‘two-lipped corolla’ lineages, reflecting notable differences in corolla morphology. Subsequent analyses were of the two sublineages separately in order to include all characters (a hypervariable region of trnG-S could not be aligned across the full range of taxa but could be aligned within sublineages). The ‘one-lipped corolla lineage’ comprises six clades of Old World taxa related as follows: [Crossandra (Sclerochiton clade {Cynarospermum [Blepharis (Acanthus clade + Acanthopsis)]})]. ...

We studied nectar characteristics in 12 species of Neotropical hummingbird-pollinated plants: Aphelandra golfodulcensis, A. sinclairiana, A. storkii, Justicia aurea (Acanthaceae); Heliconia irrasa, H. latispatha, H. mathiasii (Heliconiaceae); Pavonia dasypetala (Malvaceae); Isertia haenkeana, Palicourea guianense, Pentagonia macrophylla (Rubiaceae); and Renealmia cernua (Zingiberaceae). The diurnal patterns in sugar content and cumulative volume of nectar were documented in flowers that were protected from flower visitors. Sugar content in these species (mean of all flowers sampled per species ranged from 16 to 28%) was comparable to those reported for other hummingbird-pollinated species. Mean nectar volume per flower spanned an order of magnitude (i.e., 8.8 [Palicourea]–72.7 μl [H. latispatha]), indicating that hummingbirds visited flowers with a wide range of reward. We observed low intraspecific variation in sugar content but high variation in nectar volume. Among species, 10–50 percent of th...

We used sequence data from the intron and spacer of the trnL-trnF chloroplast region to study phylogenetic relationships among Acanthaceae. This region is more variable than other chloroplast loci that have been sequenced for members of Acanthaceae (rbcL and ndhF), is more prone to length mutations, and is less homoplasious than these genes. Our results indicate that this region is likely to be useful in addressing phylogenetic questions among but not within genera in these and related plants. In terms of phylogenetic relationships, Elytraria (representing Nelsonioideae) is more distantly related to Acanthaceae sensu stricto (s.s.) than Thunbergia and Mendoncia. These last two genera are strongly supported as sister taxa. Molecular evidence does not support monophyly of Acanthaceae s.s., although there is strong morphological evidence for this relationship. There is strong support for monophyly of four major lineages within Acanthaceae s.s.: the Acanthus, Barleria, Ruellia, and Justicia lineages as here defined. The last three of these comprise a strongly supported monophyletic group, and there is weaker evidence linking the Ruellia and Justicia lineages as closest relatives. Within the Acanthus lineage, our results confirm the existence of monophyletic lineages representing Aphelandreae and Acantheae. Lastly, within the Justicia lineage, we develop initial hypotheses regarding the definition of sublineages; some of these correspond to earlier ideas, whereas others do not. All of these hypotheses need to be tested against more data. Acanthaceae are a large family (.4000 species; Mabberley, 1987), the members of which present a rich diversity of morphological and ecological characteristics. The family is part of Lamiales s.l. (sensu lato) (i.e., sensu Olmstead et al., 1993). Unlike a number of family-level taxa in Lamiales (e.g., Lamiaceae, Verbenaceae, Scrophulariaceae), there seems little doubt that Acanthaceae s.s. (sensu stricto, see below) are monophyletic. This hypothesis is supported by the shared presence of a fruit type that is unique among angiosperms: a few-seeded, explosively dehiscent capsule within which the seeds are borne on retinacula (the lignified derivatives of funiculae). The precise delimitation of the family, however, has been controversial due to three small lineages that do not 1

ummingbirds and the flowers they visit are among the most colorful examples of mutualistic relationships between animals and flowering plants. The acrobatics, pugnacious behavior, and startling colors of many hummingbird species have won them the attention of biologists and hobbyists alike. In turn, the large and showy flowers of many of the plants pollinated by hummingbirds make them favorites of horticulturalists and well-collected by botanists. I have studied the systematics and reproductive biology of the neotropical plant genus Aphelandra (Acanthaceae). These plants have long, tubular, brightly colored (yellow, orange, red, and pink), and nectar-rich corollas that are the epitome of the hummingbird-pollinated flower (Faegri and van der Pijl 1966). From more than 100 hours spent observing visitors to Aphelandra flowers, I have documented that they are indeed pollinated by hummingbirds. Most of the plant species have strongly curved corollas that are 5.5-7 cm long (Figure la-d); these are pollinated by hermit hummingbirds (subfamily Phaethorninae), whose long, decurved bills match the

Gene flow between closely related species is a frequent phenomenon that is known to play important roles in organismal evolution. Less clear, however, is the importance of hybridization between distant relatives. We present molecular and morphological evidence that support origin of the plant genus Physacanthus via “wide hybridization” between members of two distantly related lineages in the large family Acanthaceae. These two lineages are well characterized by very different morphologies yet, remarkably, Physacanthus shares features of both. Chloroplast sequences from six loci indicate that all three species of Physacanthus contain haplotypes from both lineages, suggesting that heteroplasmy likely predated speciation in the genus. Although heteroplasmy is thought to be unstable and thus transient, multiple haplotypes have been maintained through time in Physacanthus. The most likely scenario to explain these data is that Physacanthus originated via an ancient hybridization event that involved phylogenetically distant parents. This wide hybridization has resulted in the establishment of an independently evolving clade of flowering plants.

We describe four new species of Ruellia from Costa Rica; three from the Osa Peninsula, Puntarenas province (R. exilis, R. mira, R. odorata), and one from the southwestern corner of San Jose province (R. norvegigratiosa). Ruellia matagalpae is reported as a new record for the country. New combinations are made in Ruellia for the two Costa Rican species of Blechum (R. blechum and R. costaricensis). Three species are reduced to synonymy, and another species is considered doubtfully worthy of recognition. Notable range extensions are reported for two species. Corollas and fruits of all 22 Costa Rican species of Ruellia are shown and compared as easily used identification aids. An informal guide to species groups and a dichotomous key to the 22 species are presented.

We used sequence data from the nuclear ribosomal internal transcribed spacer (nr-ITS) region, both alone and in combination with data from the intron and spacer of the trnL-trnF chloroplast (cp) region, to study phylogenetic relationships within the large tropical and subtropical family Acanthaceae. Substitution rate in the nr-ITS region is nearly twice that of the trnL-trnF cp region, and more than twice the rates of other cp loci that have been sequenced for members of Acanthaceae (i.e., rbcL, ndhF). In terms of phylogenetic relationships, the hypothesis based on ITS was largely congruent with the trnL-trnF results. Exceptions are Crossandra pungens and the two Acanthus species, which are placed enigmatically by nr-ITS data. The combined analysis provides strong support for a single hypothesis of relationships among Acanthaceae sensu stricto (s.s.) and their closest relatives. 1) Elytraria (representing Nelsonioideae) is more distantly related to Acanthaceae s.s. than Thunbergia and Mendoncia. ...

Controlled pollinations, followed by germination studies of seeds resulting from selfand cross-pollination, were carried out using plants from 12 populations of nine species of Aphelandra (Acanthaceae), a genus of neotropical shrubs and herbs. These results are combined with data from field studies of flower morphology, phenology, and pollinator relationships to estimate breeding system of each species. All species have floral morphological traits that prevent autogamy. Plants from five populations of five species experience low levels of geitonogamous pollen transfer; they produce few flowers daily and are pollinated by traplining hummingbirds. Excepting A. storkii, these plants are fully self-compatible (SC), and seeds from selfing are as viable as crossed seeds. Aphelandra storkii is partially self-incompatible (SI) and produces seeds from selfing that tend to germinate less successfully than crossed seeds. Plants from the remaining populations are profusely flowering shrubs, and even those pollinated by traplining hummingbirds should experience higher levels of geitonogamy. Aphelandra deppeana is pollinated by territorial hummingbirds, which should further increase the incidence of geitonogamy. All shrub species are partially SI, and two species (A. Ieonardii and A. sinclairiana) show significant reduced germination of selfed vs. crossed seeds. The breeding system of these species is thus modified by postpollination factors that favor the formation and maturation of outcrossed seeds. It is suggested that Aphelandra species, like other herbs and shrubs of tropical forest understory, possess a combination of breeding system traits that promote outcrossing but do not exclude

The newly described species are Central American members of the Aphelandra pulcherrima complex (Acanthaceae). Aphelandra panamensis McDade occurs in cloud forests at middle elevations in central and eastern Panama. Aphelandra golfodulcensis McDade is found in southwestern Costa Rica and adjacent Panama at low to middle elevations. Aphelandra leonardii McDade is known from the lowlands of eastern Panama and from middle elevations in central Costa Rica. The Aphelandra pulcherrima complex is a morphologically well-defined group of about 35 species found in South and Central America. Features distinguishing these species from other Aphelandra include extrafloral nectaries on the floral bracts and a distinctive corolla morphology (Leonard, 1953; McDade, 1980). In the course of revisionary work on the Central American species of this complex (McDade, 1980), three new species belonging to the group were discovered. Aphelandra panamensis McDade, sp. nov. TYPE: Panama, Panama, Slopes of Cerro Jefe, past Goofy Lake and large coffee finca, 800 m elev., McDade 411 (DUKE, holotype; F, MO, isotypes).-FIG. 1. Frutex 1-6 m altus; foliis ellipticis, 15-18 (22) cm longis, 3-6.5 cm latis. Inflorescentiae spicatae, terminales, sessiles, 1-5, 4-12 cm longae, 0.8-1.2 cm latae; rachis dense pubescens; bracteae imbricatae, rhombeo-ovatae, dentatae, 11-15 mm longae, 6-8 mm latae, virides vel sordide aurantiacae, nectaria 5-10 glandibus, glandes singulae 0.5 mm longae, 0.3 mm latae; bracteolae lanceolatae, 6-10 mm longae, 1.5-2.5 mm latae. Calycis lobi lanceolati vel anguste-ovati, 8-12 mm longi, 1.5-5 mm lati; corolla rubra, 5.5-7.0 cm longa, tubo 5 cm longo, labium superum 14-20 mm longum, 6-8 mm latum, lobus medius labi inferiores 18-23 mm longu, 4-7 mm latu; antherae 4-5 mm longae; stigma obliquum et cavum. Fructus immaturi sordide aurantiaci, 16-19 mm longi, 4.5-6.5 mm lati, 5.5-7 mm crassi; seminae atrobrunneae, orbiculares, 4-6 mm in diam., 2-3 mm crassae. Germinatio semihy

Counts of pollen grains on the stigmas of individual flowers of Trichanthera gigantea in Central Panama were related to seed set. At least eight grains were necessary for fruit set in this species and mean seed set per fruit was less than one (of a maximum of eight). Less than 50 percent of the flowers (108 of 277) received eight or more pollen grains and, of these, only 5 1 set fruit. These results suggest that pollination limits seed production by this species at this site.

New species of Justicia and Razisea are described from the Caribbean lowlands of northern Costa Rica. Justicia sarapiquensis sp. nov. is an unusual vine with large, magenta bracts and white, villous corollas. While morphologically most similar to several large-bracted South American justicias, the echinulate pollen grains of this species suggest a relationship with Rhacodiscus. This genus was distinguished fromJusticia on the basis of echinulate pollen and appears to be an artificial grouping of species better placed within Justicia. Clarification of the relationships of Justicia sarapiquensis will await resolution of this large and taxonomically difficult genus as a whole. The four species currently placed in Razisea share several unusual features including monothecate anthers and corolla with the upper lip strongly reduced and the lower lip barely distinct from the tube. Pollen analysis of Razisea wilburii sp. nov., along with literature reports of pollen of the remaining species, indicates that this genus is incorrectly placed in Justiceae, Odontoneminae. Based on pollen evi- dence, as well as the long-recognized similarity between Razisea and Kalbreyeriella, it is recommended that Razisea be moved to Justiceae, Justiciinae. In the course of field work in the Caribbean lowlands of northern Costa Rica, previously undescribed species belonging to two genera of Acanthaceae were discovered. This region of Costa Rica is particularly poorly known botanically and it is expected that further collections will result in a better understanding of the ranges of these two species. The extensive collecting being carried out toward completion of a flora for the La Selva field station of the Organization for Tropical Studies will greatly expand our knowledge of the plants of this extremely diverse area.