Some Evolutionary Trends in the Bambusoideae (Poaceae)

prier which have woody culms, and several genera with herbaceous culms share a similar type of leaf anatomy and epidermis.Various other morphological features, including a distinctive a of seedling, also indicate a close relationship that supports the grouping of these genera together into a single subfamily, the Bambusoideae.A review of the chromosome numbers in the subfamily reveals that the herbaceous members are mostly diploid while the woody ones are polyploid, with x = 12 the basic number.Such evidence corroborates the hypothesis that bamboos have been derived from herbaceous ancestors.Most bamboos flower infrequently and have had far less opportunity for ized ones have developed in the herbaceous members.A knowledge of ps former type of inflorescence is useful in an interpretation of the latter.With this in mind, the inflorescence of the herbaceous bambusoid grass, Streptochaeta, has been reexamined.This genus has long been considered to be ted as a primiti parted p : Comparison of Streptochaeta with other ue. of the Ba eee suggests that the spikelet in genera like Sii iiic BIrepi gana, and Pharu he significant trends of evolution within the subfamily become apparent, however, only when all of the genera-woody and herbaceous-are considered together.The bambus oid line-with its complex leaf anatomy and epidermis-is itself specialized and not to be regarded as the precursor of the other groups of grasses.