Somatic Chromosome Counts In Some Species Of Crassocephalum (Moench.) S. Moore (Asteraceae) In Southwestern Nigeria.

Somatic chromosome numbers of four species in the genus Crassocephalum were counted. Basic chromosome number of n=10 which was tentatively suggested for the genus by previous workers was confirmed. Three species, Crassocephalum rubens (Juss.ex.Jacq) S. Moore, C. biafrae (Oliv.& Hiern) S. Moore and C. togoense C.D. Adams had chromosome numbers of 2n=20 while 2n=40 was reported for the C. crepidioides (Benth.) S. Moore. The occurence of higher chromosome number in C. crepidioides suggests the species to be polyploid. Basic chromosome number of n=10 was confirmed for the genus.