Frank Almeda

Phylogeny of Miconia (Melastomataceae): Patterns of Stamen Diversification in a Megadiverse Neotropical Genus

Phylogenetic relationships within Miconia and other genera in the Neotropical tribe Miconieae were investigated using a maximum parsimony analysis of nuclear internal transcribed spacer and ndhF nucleotide sequences. Included were all sections in Miconia (212 species, ∼20% of the genus) and 12 of the 15 remaining genera assigned to the tribe (an additional 239 species). Given the tribe’s reputation for problematic generic distinctions, it was not surprising that most traditionally recognized taxonomic groups—both genera and sections—were shown to be polyphyletic or paraphyletic. Nevertheless, Miconia is composed of several distinct monophyletic groups, with a large majority of the species belonging to only four clades. Some of these groups represent parts of sections proposed in the last revision of the genus, but most of the diversification seems to have occurred in geographical areas that are more restricted than would have been predicted by the distribution of these sections. Moreover, parallel evolutionary trends are seen in anther form, i.e., shifts from elongate to shorter anthers and from minute‐pored to large‐pored or slitlike dehiscent anthers. These changes may relate to pollinator shifts, especially from buzz pollination to nonvibrational pollination. Thus, the major evolutionary diversifications within the tribe have been obscured by convergence in stamen morphology, leading to many arbitrary generic and sectional circumscriptions.

Phylogeny and infrageneric classification of Symplocos (Symplocaceae) inferred from DNA sequence data

Symplocos comprises ∼300 species of woody flowering plants with a disjunct distribution between the warm-temperate to tropical regions of eastern Asia and the Americas. Phylogenetic analyses of 111 species of Symplocos based on the nuclear ribosomal internal transcribed spacer (ITS) region and the chloroplast genes rpl16, matK, and trnL-trnF yielded topologies in which only one of the four traditionally recognized subgenera (Epigenia; Neotropics) is monophyletic. Section Cordyloblaste (subgenus Symplocos; eastern Asia) is monophyletic and sister to a group comprising all other samples of Symplocos. Section Palura (subgenus Hopea; eastern Asia) is sister to a group comprising all other samples of Symplocos except those of section Cordyloblaste. Symplocos wikstroemiifolia (eastern Asia) and S. tinctoria (southeastern United States), both of subgenus Hopea, form a clade that groups with S. longipes (tropical North America) and the species of subgenus Epigenia. The remaining samples of subgenus Hopea (eastern Asia) form a clade. Section Neosymplocos (subgenus Microsymplocos; Neotropics) is well nested within a clade otherwise comprising the samples of section Symplocastrum (subgenus Symplocos; Neotropics). Section Urbaniocharis (subgenus Microsymplocos; Antilles) groups as sister to the clade comprising Symplocastrum and Neosymplocos. The data support the independent evolution of deciduousness among section Palura and S. tinctoria. The early initial divergence of sections Cordyloblaste and Palura from the main group warrants their recognition at taxonomic levels higher than those at which they are currently placed. An inferred eastern Asian origin for Symplocos with subsequent dispersal to the Americas is consistent with patterns from other phylogenetic studies of eastern Asian-American disjunct plant groups but contrary to a North American origin inferred from the earliest fossil occurrences of the genus.

Henrietteeae (Melastomataceae): A New Neotropical Berry-Fruited Tribe

Abstract With nearly 2,000 species, all restricted to the Neotropics, Miconieae represent the largest radiation within Melastomataceae. Generic limits and relationships within the tribe have long been contested. Our molecular phylogenetic analyses of the tribe, based on sequences of nrITS and ndhF, resulted in consistent support for a clade comprising Bellucia, Loreya, Henriettea, and Henriettella, which is neither nested within nor sister to the Miconieae. Furthermore, and based upon a series of presumably synapomorphic anatomical and morphological characters, e.g. megastyloid crystals, absence of both medullary and cortical vascular bundles, plinerved leaves, axillary or cauliflorous inflorescences, we consider three additional genera, Kirkbridea, Llewelynia, and Myriaspora, to belong to this clade, a newly recognized tribe, Henrietteeae. These seven genera had formerly been assigned to the Miconieae based on their having exappendiculate anthers (except Kirkbridea) and berry fruits. Henriettella and Llewelynia are relegated to synonymy under Henrietten (25 new combinations are made under that genus: Henriettea boliviensis, H. bracteosa, H. caudata, H. duckeana, H. fissanthera,H. glabra,H. cogniauxiana, H. goudotiana,H. heteroneura, H. hondurensis, H. ininiensis, H. lawrancei, H. lundellii, H. maguirei, H. manarae, H. odorata, H. ovata, H. prancei, H. rimosa, H. steyermarkii, H. tachirensis, H. tobagensis, H. tovarensis, H. trachyphylla, H. williamsii), and Loreya and Myriaspora are synonymized under Bellucia (with nine new combinations under that genus: Bellucia egensis, B. gracilis, B. klugii, B. nigricans, B. ovata, B. riparia, B. strigosa, B. subandina, B. wurdackiana). A description of Henrietteeae along with a key to and brief descriptions of its constituent genera are provided, in addition to necessary new combinations.

Phylogeny of Symplocos Based on DNA Sequences of the Chloroplast trnC-trnD Intergenic Region

Abstract Phylogenetic analysis of 74 species of Symplocos was conducted with DNA sequence data from the chloroplast trnC-trnD intergenic region. Maximum parsimony and Bayesian inference trees are consistent with those of a previous study based on combined data from the nuclear ribosomal ITS region and the chloroplast regions rpl16, matK, and trnL-trnF. The inclusion of 21 phylogenetically informative indel characters from trnC-trnD resulted in greater maximum parsimony resolution and clade support than with these characters excluded. A combined five-gene-region (trnC-trnD, ITS, rpl16, matK, and trnL-trnF) analysis based on a data set with complete sequence data is almost completely concordant with that of the combined four-gene data set, and displays higher resolution and overall clade support (in some cases 20 to > 30 bootstrap percentage points). The data indicate monophyly for only one subgenus (Epigenia) and four sections (Barberina, Cordyloblaste, Neosymplocos, and Urbaniocharis) of Symplocos; the other three subgenera (Symplocos, Hopea, and Microsymplocos) and tested sections (Bobu, Palaeosymplocos, and Symplocastrum) will require recircumscription to accord with the principle of monophyly. Supermatrix and supertree analyses were conducted to provide phylogenetic estimates based on all 107 available Symplocos samples with sequence data from at least two of the five gene regions. The supermatrix consensus tree is completely consistent with that from the combined five-gene estimate based on complete sequence data, whereas the supertree consensus differs from these trees in two regions of the topology. The supermatrix consensus also displays greater clade resolution than the supertree consensus. The aligned trnC-trnD data set exhibits a lower percentage of parsimony-informative characters than those based on matK and rpl16 sequences. The length, organization, and relative sequencing ease of trnC-trnD in Symplocos nonetheless confirm the utility of this region for phylogenetic estimation in flowering plants, as previously described.

Rupestrea: A New Brazilian Genus of Melastomataceae, with Anomalous Seeds and Dry Indehiscent Fruits

Abstract The genus Rupestrea is described to include two species previously described in Miconia. Rupestrea carvalhoana and R. johnwurdackiana are restricted to Campos Rupestres at the northern portion of the Chapada Diamantina in Bahia, Brazil. The genus can be recognized by the dry and indehiscent fruits that may be hydrochorous, and by the orthocampylotropous, monoembryonic seeds, each incompletely divided into two cavities by a septum. The genus is sister to a large clade that includes the capsular-fruited tribes Melastomeae, Microlicieae, and Rhexieae.

Cryptic dioecy is widespread in South American species of Symplocos section Barberina (Symplocaceae)

Pollen morphology of ten Brazilian species within the South American clade (ca. 20 species) of Symplocos section Barberina (Symplocaceae) was analyzed with scanning electron microscopy to assess their reported androdioecious breeding system. All species exhibited pollen dimorphism. Pollen from male individuals is well developed and 3-colporate, whereas that from morphologically hermaphroditic individuals is malformed, often completely fragmented, lacks cytoplasm, and has no germination pores. Our results suggest that the morphologically hermaphroditic species of S. section Barberina with malformed pollen are cryptically dioecious.

A synopsis of the genus Blakea (Melastomataceae) in Mexico and Central America

A regional synopsis of the genus Blakea is presented that recognizes 33 species in Mexico and Central America. This summary includes a key, distributional and phenological information, notes on morphological variation, and discussions that provide rationale for relegating six binomials to synonymy. Descriptions and diagnoses are presented for four new species of Blakea (B. coloradensis, B. darcyana, and B. perforata from Panama; and B. wilsoniorum from southern Costa Rica and Panama). Analysis of the type specimens and recently collected flowering material of Topobea storkii necessitates its transfer to Blakea. Three other species (B. cuatrecasii, B. repens, and B. subconnata var. obtusa), all of which were previously known from Andean South America, are reported from Panama for the first time. Blakea, with approximately 100 species, is one of two berry-fruited genera comprising the natural neotropical tribe Blakeeae (Almeda, 1990). It is best represented in wet montane regions from southern Mexico and the West Indies to Bolivia and Brazil. Although northwestern South America is undoubtedly the center of species richness for Blakea (Wurdack, 1973), southern Central America is clearly the area of focal importance for unusual diversity in floral morphology. This floral diversity reflects adaptations to a broad array of important pollinators in the region, including rodents, buzzing bees, and hummingbirds (Almeda, 1990; Lumer, 1981; Lumer & Schoer, 1986). For a woody genus with showy, often spectacular, flowers, it is surprising that Blakea has escaped the attention of serious students until recently. The genus has not been treated in its entirety since Cogniauxs (1891) familial monograph. Even the most recent floristic treatments of the family Melastomataceae for the Mesoamerican region appeared over 30 years ago (Gleason, 1958; Standley, 1924, 1938; Standley & Williams, 1963; Winkler, 1965) when many areas were still little-explored and poorly known botanically. The account presented here is a precursor to the treatment that will appear in Flora Mesoamericana. Four new species and one new generic transfer are proposed in the context of a regional synopsis. This summary also includes a key to the 33 recognized species, distributional and phenological information, notes on variation, and discussions that provide rationale for relegating previously recognized species to synonymy.

Stanmarkia, a new genus of Melastomataceae from the volcanic highlands of western Guatemala and adjacent Mexico

A new genus,Stanmarkia, is described from the volcanic highlands of western Guatemala and adjacent Chiapas, Mexico to includeS. medialis, comb. nov. andS. spectabilis, sp. nov. Among the Melastomataceae,Stanmarkia is distinguished by its 5-merous flowers, subequal stamens that lack prominently developed appendages or prolonged connectives, terete hypanthia, and clavate-cuneate seeds that have an enlarged excurrent arilloid raphe and a tuberculate seed coat. A gametic chromosome count ofn=40 is reported here forS. spectabilis. This count, which is clearly of polyploid origin, represents a new definitive number for the family. An emphasis on seed characters suggests placement ofStanmarkia in the Sonerileae which is here interpreted in a broad sense to include all genera previously assigned to the New World Bertolonieae and the Old World Oxysporeae. A consideration of other characters such as configuration of the ovary apex, capsule morphology, and androecial details also provides evidence for placement ofStanmarkia in the Merianieae.

Seed Diversity in the Tribe Miconieae (Melastomataceae): Taxonomic, Systematic, and Evolutionary Implications

Miconieae is the largest tribe in the Melastomataceae with over 1,850 species. The members of Miconieae display a wide range of morphological diversity, and seed morphology is no exception. Previous studies have found that seed morphological diversity is not congruent with traditional classifications, and suggest that it may reflect evolutionary relationships within Miconieae. Here we characterize seed morphology of 364 species of Miconieae. The morphological data set and a DNA sequence data matrix were analyzed under a parsimony and Bayesian framework. Seed characters were used to test taxonomic and clade hypotheses, to estimate morphological ancestral character states, and to assess phylogenetic signal. The phylogenetic analyses of morphological data retrieved a poorly-resolved, low-supported phylogeny; in contrast, a relatively strongly supported phylogeny was estimated using the molecular data. Hypothesis testing procedures could only reject the monophyly of Clidemia, Leandra, and Miconia. The results indicated that the seed morphological characters were homoplasious, but contained phylogenetic signal. The morphological seed types that were described in previous studies did not support any of the clades retrieved by the molecular phylogeny. In contrast with previous investigations, our study shows that although seed morphology is very variable, it does not provide information for supporting some genera or clades within Miconieae. However, it is suggested that seed characters in combination with other vegetative and reproductive traits may aid in the characterization of smaller clades. The presence of phylogenetic signal retrieved by homoplasious characters may indicate that diversification of seed characters could have an adaptive component. Further studies that increase taxon sampling, refine seed trait characterization, and evaluate the alleged relationships between environmental variables and seed diversification will contribute to a better understanding of seed morphology and evolution in this species-rich tribe.

CliNAl vARiATioN ANd The deCouPliNg oF vegeTATive ANd RePRoduCTive ChARACTeRs iN AcisAntherA seCTioN AcisAntherA (MelAsToMATACeAe)

Abstract Clinal variation in morphology from north to south and to a lesser degree from east to west is described in the widespread Neotropical species of Acisanthera sect. Acisanthera. While northernmost and southernmost species are separable from one another, they are bridged by other species which results in a complicated morphological continuum. Two important characters were detected in the data that correlate with geographic distribution: first, flowers on compound inflorescences in plants south of Amazonia and with solitary flowers north of Amazonia; and second, anther pore width from narrow (0.2 mm) in South America to wide (0.38 mm) mainly in Central America and the Caribbean. A high degree of plasticity in the first character south of Amazonia (inflorescence structure) complicates differential diagnosis between species in the southern end of their distribution. Adding leaf shape and indument helps differentiate the currently recognized species although in some cases with difficulty. These cases are discussed particularly in reference to Acisanthera variabilis. Although most continuously varying vegetative characters are positively correlated with geography, two floral characters are not (anther pore width and anther appendage connective length) which suggests differing selection pressures. Overall, partitioning of vegetative from reproductive characters indicates they are uncoupled, a result which supports Bergs correlation-pleiades hypothesis.