Taxonomic studies in the Miconieae (Melastomataceae). IX. Calycogonium formonense, a new species from the Massif de la Hotte, Haiti

Calycogonium formonense, a new species, is here described from the floristically diverse Massif de la Hotte of southern Haiti. It is compared to C. hispidulum, to which it is likely related. Although the genus Calycogonium is not monophyletic, C. formonense and C. hispidulum are probably related to other species, e.g., C. calycopteris, C. heterophyllum, and C. reticulatum, that exhibit reduced inflorescences and 4-merous flowers having hypanthia with four conspicuous lobes separated by longitudinal grooves and external calyx lobes that are flattened parallel to the floral radii. These distinctive species may form a clade. Calycogonium formonense is distinguished from C. hispidulum by its smaller leaves with the tertiary veins not raised on the abaxial surface, with entire margins (i.e., margin without elongate multicellular hairs), and usually solitary flowers.     

Taxonomic studies in the Miconieae (Melastomataceae). VI. Miconia santanana,a new species from Hispaniola

Miconia santanana, which occurs in broad-leaved forests along streams of pineland habitats in the Cordillera Central of the Dominican Republic, is described and illustrated. It is compared withM. ferruginea andM. adenocalyx, two presumed close relatives withinMiconia sect.Chaenopleura. Eco-geographic characterizations and a key are presented for these three species.     

Mecranium juddii (Melastomataceae: Miconieae), a new species from the Massif de la Hotte, Haiti

Mecranium juddii is described and illustrated. It is known only from 1650–1700 m elevation in the Ravine du Sud on the northern slopes of Morne Formon in Macaya National Park, Haiti.Mecranium juddii is a member of theM. multiflorum complex and is phenetically most similar toM. revolutum andM. alpestre, which differ fromM. juddii in stem indumentum or leaf size and shape.     

Miconia zanonii (Melastomataceae: Miconieae), a new species from Hispaniola

Miconia zanonii, which occurs in broad-leaved cloud forests at four localities in the Cordillera Central of the Dominican Republic, is described and illustrated. It is compared withM. krugii andM. samanensis, two probably close relatives withinMiconia sect.Chaenopleura.     

Una nueva especie de <Emphasis Type="Italic">Miconia</Emphasis> (Melastomataceae: Miconieae) de Colombia

Miconia punctibullata, a new species of Melastomataceae from Colombia, is described and illustrated. The new species can be distinguished by its scandent herbaceous habit, stems and inflorescences with swollen annular projections below the nodes, punctations with sessile, glandular trichomes on the abaxial surface of the leaf, compound dichasial inflorescences, and bright yellow petals. A key to all species of Miconia with annular stem projections is provided.

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Resumen  Se describe e ilustra Miconia punctibullata, una nueva especie colombiana de Melastomataceae, caracterizada por el hábito herbáceo semiescandente, la presencia de proyecciones anulares engrosadas por debajo de los nudos (manicaduras) en tallos y ejes de la inflorescencia, punteaduras con tricomas glandulares sésiles por el envés de la lámina foliar, inflorescencias en dicasio compuesto, y pétalos amarillos. Se incluye una clave para todas las especies de Miconia con nudos manicados.

     

Comparative seed morphology of <Emphasis Type="Italic">Leandra</Emphasis> (Miconieae,Melastomataceae)

The seed morphology of 79 species of neotropical Miconieae (Melastomataceae) is presented. These species have been chosen, in majority, from the polyphyletic genus Leandra. A few other species from the polyphyletic genera Miconia, Ossaea, and Clidemia were also sampled, because of potential similarities. Sixteen morphological seed types are defined after analysis through light microscopy and scanning electron microscopy. The seed morphology appears to possess a great deal of variability on the level of the overall shape as well as the structure and the surface of the testa. The different types defined here do not match with genera or sections, but rather are composed of species coming from different genera. In comparison with a preliminary molecular phylogeny study done on Leandra, some types of seeds are related to well supported clades. In some cases seed morphology corresponds with natural groups of species, thus being of high phylogenetic importance.     

Taxonomic studies in the Miconieae (Melastomataceae). I. Variation in inflorescence position

In the Miconieae (Melastomataceae) the inflorescences may be either lateral (with shoots pleonanthic and plants showing Rauh's architectural model) or the terminal (with shoots hapaxanthic and plants illustrating Leeuwenberg's, or less commonly Scarrone's or Stone's, architectural models). Inflorescence position is a valuable taxonomic character in the tribe and is usually uniform within genera or speciesgroups. An analysis of variation of this character elucidates the complex and difficult generic delimitations within the tribe.Ossaea DC. andClidemia D. Don, as presently delimited, contain both terminal-and axillary-flowered species and are undoubtedly polyphyletic assemblages. Some groups, e.g.,Clidemia sect.Clidemia, Leandra Raddi sect.Chaetodon Cogn.,Ossaea sect.Octopleura (Griseb.) Cogn., andMyrmidone Mart. have species that develop pseudolateral inflorescences, i.e., the terminal nature of the inflorescence is obscured by the early development of an axillary bud which continues growth of the branch. Pseudolateral inflorescences seem to have evolved several times within the tribe, andClidemia sect.Clidemia likely evolved from the obviously terminal-floweredHeterotrichum DC. andMiconia Ruíz & Pavón sect.Octomeris Hook. f. (p. p.);Myrmidone andMicrophysca Naud. are closely related toTococa Aublet; andLeandra sect.Chaetodon (and probably alsoOssea sect.Octopleura) show affinity with the remaining sections ofLeandra.     

Pereskia marcanoi,a new species of Cactaceae from Hispaniola

Pereskia marcanoi is newly described from the rocky hillsides of Cerro San Francisco (Bánica), western Dominican Republic. With three other species from Hispaniola and Cuba, this new taxon forms a unique group of functionally dioeciousPereskia species native to the West Indies. Some important diagnostic characters of the members of this group are contrasted in key form.     

Ten new species of Tibouchina (Melastomataceae) from Mexico

Ten new species of Tibouchina (T. almedae, T. congestiflora, T. connata, T. hintonii, T. macvaughii, T. nanifolia, T. patens, T. roseotincta, T. sinaloensis, andT. thulia) are described from western Mexico. Distinguishing characteristics, phenology, distribution, and phylogenetic relationships are discussed. Illustrations of all these new species are provided.     

Two new species of Huberia (Melastomataceae: Merianieae) from Brazil

Two new Brazilian species of the genusHuberia,H. carvalhoi andH. consimilis, are described, discussed, and illustrated.Huberia carvalhoi is endemic to Bahia;H. consimilis has a wider distribution, with disjunct populations in Pernambuco, Bahia, and Rio de Janeiro. A key is provided to the three Bahia taxa with some comments on the taxonomic affinities of the two new species.     

A new species of Henriettea (Melastomataceae) from the Sierra de Baoruco, the Dominican Republic

Henriettea uniflora, which is known only from a diverse moist montane forest in the vicinity of Loma Trocha de Pey (or “Monteada Nueva”), Loma Pie de Palo, and Loma Remigio, the easternmost peaks of the Sierra de Baoruco, is described and illustrated. It is compared to species of the Henriettea squamulosa complex, especially H. squamulosa and H. ciliata. The species of this complex are characterized by an indumentum of ferruginous, stellate-lepidote hairs.     

A new species of Microlicia (Melastomataceae) from Brazil

A new species of the genusMicrolicia,M. flava, from the highland “campo rupestre” vegetation of Serra da Canastra National Park, São Roque de Minas, Minas Gerais, Brazil, is described and illustrated.     

Three new species of melastomataceae from the southeastern Atlantic Forest of Brazil

Three species are described here that occur in montane and high-montane forests in Southeastern Brazil.Miconia shepherdii belongs to sectionGlossocentrum and occurs on the Serra da Mantiqueira, on the border between the states of São Paulo, Minas Gerais, and Rio de Janeiro.Miconia kollmannii belongs to sectionHypoxanthus (formerChaenanthera) and occurs in the state of Espírito Santo.Ossaea suprabasalis was also collected in the state of Espírito Santo.     

Dioscorea howardiana,a new species in Dioscorea section Trigonobasis (Dioscoreaceae)

Dioscorea howardiana is proposed as a new species from Mexico and Central America as far south as Panama, and is described and illustrated. It most closely resemblesD. liebmannii. Relationships, distribution, and ecological preferences of the new species are discussed.

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Resumen   Dioscorea howardianase propone como una especie nueva de México y Centroamérica, es descrita e ilustrada. Es semejante aD. liebmannii. Se discuten sus relaciones, su distribución geográfica y preferencias ecológicas.

     

Jacquinia pauciflora (Theophrastaceae), a new species from Puerto Rico

A new species,Jacquinia pauciflora, is described from subtropical moist forest on karst hills (mogotes) in northwestern Puerto Rico.Jacquinia pauciflora is similar toJ. stenophylla Urban, from which it differs in several floral and leaf characters, but is possibly most closely related toJ. umbellata A. DC. A key to the species ofJacquinia occurring in Puerto Rico is provided.     

Photosynthetic responses of Miconia species to canopy openings in a lowland tropical rainforest

We examined the photosynthetic acclimation of three tropical species of Miconia to canopy openings in a Costa Rican rainforest. The response of photosynthesis to canopy opening was very similar in Miconia affinis, M. gracilis, and M. nervosa, despite differences in growth form (trees and shrubs) and local distributions of plants (understory and gap). Four months after the canopy was opened by a treefall, photosynthetic capacity in all three species had approximately doubled from closed canopy levels. There were no obvious signs of high light damage after treefall but acclimation to the gap environment was not immediate. Two weeks after treefall, A_max, stomatal conductance, apprarent quantum efficiency, and dark respiration rates had not changed significantly from understory values. The production of new leaves appears to be an important component of light acclimation in these species. The only variables to differ significantly among species were stomatal conductance at A_max and the light level at which assimilation was saturated. M. affinis had a higher stomatal conductance which may reduce its water use efficiency in gap environments. Photosynthesis in the more shade-tolerant M. gracilis saturated at lower light levels than in the other two species. Individual plant light environments were assessed after treefall with canopy photography but they explained only a small fraction of plant variation in most measures of photosynthesis and growth. In conclusion, we speculate that species differences in local distribution and in light requirements for reproduction may be more strongly related to species differences in carbon allocation than in carbon assimilation.