Estudos taxonomicos no genero Paspalum L., grupos "Virgata" e "Quadrifaria" no Brasil

AUTOR(ES)
DATA DE PUBLICAÇÃO

1995

RESUMO

The present work consists of taxonomic studies with the "Virgata" and "Quadrifaria" groups of Paspalum L. represented by their species in Brazil. The study was realized with living specimens mantained in experimental gardens and herbarium material and offers detailed descriptions, distribuition maps, leaf blade anatomy and numerical analysis though grouping techniques. The "Virgata" group represented by Paspalum viragtum, P. commúne, P. conspersum, P. regnellii, P. rufum e P. wettsteini and the "Quadrifaria" group compoused by P. quadrifarium, P.intermedium, P. densum, P. millegrana,P. durifolium, P. brunneum, P. usteri,P. plenum, P. coryphaeum, P. exaltatum e P. haummanii are well represented in Brazil, with their greatest number of speciesin South, South-West and Middle-West regions. The caracters utilized for recognition of the groups are related to the habit, piramidal or quadrangular inflorescence and to anthecium colour which can be yellowish or brown. The spikelet structure and parts are the most important and diagnostic features at the species leveI. The anatomic studies furnished informations about species not yet described anatomically and also used to amplify the existent descriptions, although they were not emploied in the taxonomic delimitacion of the species and their groups. The numerical analysis allowed an evaluation of the "Virgata" and "Quadrifaria" groups because they enclosed all the variability found in the analysis of the material. The superposition of the types phenograms indicates that the absence of the clear limits show inconsistency and question the position of the natural groups. Despite this fact they show a defined grouping for the complex formed by P. coryphaeum. P. quadrifarium, P. brunneum e P. usteri enclosed in ?Quadrifaria" group, and characterized by fragiles plants. As a first step in the identification of highly related species, the "Virgata" and ?Quadrifaria" groups are taken as valid, although a critical view of their limits is here introduced

ASSUNTO(S)

taxonomia numerica anatomia vegetal morfologia

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