Estudos morfológicos e filogenéticos de Sebastiania Spreng. (Hippomaneae, Euphorbiaceae). / Morphological and phylogenetics studies at Sebastiania Spreng. (Hippomaneae, Euphorbiaceae).

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

11/02/2011

RESUMO

Hippomaneae (Euphorbiaceae) has 33 genera standing out Sebastiania including about 25 species. Sebastiania is a promising group to realize a phylogenetical studies, because of the representativeness in the Brazilian flora, morphological complexity, imprecise specific composition and because is polyphyletic. The aims of this work were understand Sebastiania circumscription through phylogenetical hypothesis and to supply morphological characters of the fruits and seeds useful for determination of the affinities in the American genera of the Hippomaneae. For the morphological and molecular analysis were used 30 species of Sebastiania (19) Colliguaja (1), Dendrocousinsia (1), Gymnanthes (3), Hippomane (1), Microstachys (3), Pleradenophora (1) and Spirostachys (1). The phylogenetic study of Sebastiania based on individual and combined morphological and trnL-F. The maximal parcimony analysis morphological+trnL-F resulted in 2000 trees similarly parcimonious with a consistence index (CI) = 0,45 and retention index (RI) = 0,63. Sebastiania it show polyphyletic because some of its species grouped together to the Gymnanthes and Spirostachys and other occurred in basal position in the phylogeny. However, a clade which includes the majority of the species of Sebastiania (Sebastiania s. str.) is monophyletic when are included Microstachys ramosissima and Gymnanthes integra and is sustained by sinapomorphies: absence of stamens sepals covering to the anthers in pre-anthesis, septum fruit shaped, mericarp with separate basal triangle, columella apex shaped, projection fleshy adhered to the columella after fruit dehiscence, seed smooth and without caruncle. Its suggested the transfer of species S. lottiae, S. membranifolia, S. panamensis and S. tikalana of the Sebastiania circumscription. Besides, attributes such as type and dehiscence of fruit,surface texture, mericarp with separate basal triangle, columella apex shaped, presence of caruncle and aril were useful for the delimitation of the Hippomaneae genera.

ASSUNTO(S)

taxonomia morfologia cladística botanica morphology taxonomy cladistic euphorbioideae

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