On the basis of morphological characters, twenty indigenous and exotic collections of Panicum maximum Jacq. have been classified into five broad types. Morphology (including detailed floral morphology) of these types is described with illustrations. A considerable range of variation of taxonomic significance was met with in them in respect of several characters, both vegetative and floral. Some new characters of diagnostic value, which do not seem to have been reported upon for this species earlier, are described and a handy key to their identification given.
The seed progenies of these morphologically-distinct types were matromorphic and hence exhibited remarkable uniformity within themselves, indicating that the species is highly apomictic.
Some of these types exhibited characters which are considered to be relatively primitive; these characters are described and them phylogenetic significance indicated. Some evolutionary trends in this complex, heterogeneous taxon are discussed.