Somatic Chromosomes of Leptaspis and Streptogyna (Poaceae)

Abstract

BOTH Leptaspis and Streptogyna represent very interesting groups from the point of view of the phylogeny of the Poaceae as their external morphology is very primitive. I collected Leptaspis cochleata Thw. and Streptogyna crinita Beauv. in woods at Dulva Kanda (about 4,000 ft.) in Ceylon while I was there in 1957. The root tips of the two species were fixed with Navashin solution at the habitats and, after my return to Japan, dehydrated and embedded in paraffin. Sections were cut at 15µ and stained by Newton's gentian violet method. Two individuals of S. crinita and one individual of L. cochleata were used for chromosome observation. As shown in Figs. 1 and 2, both species had 2n = 24. The chromosomes of L. cochleata are clearly larger than those of S. crinita.