CYTOTAXONOMIC STUDIES ON SOME SOUTHERN NIGERIA ASTERACEAE - TRIBE SENECIONEAE

Abstract

Cytological and morphological studies were carried out on 19 taxa belonging to 4 genera and 12 species of the southern Nigerian Asteraceae Meiosis was normal and the plants were stable. Chromosome counts of Crassocephalum bauolense (n = 10), C. bougheyanum (n = 12), C. sarcobasis (n = 16) and Crassocephalum sp (n = 16), were new reports for these species, while those of Emilia praetermissa, (n = 12), C. rubens white and pink varieties (n = 12) and C. montuosum (n = 24) differed from earlier reports. The report of 2 cytomorphovariants C. rubens (n = 10, 12) and Emilia praetermissa (n = 10, 12) is reported for the first time for the tribe from Nigeria. New base numbers of 6 and 8 have been suggested for the genus Crassocephalum, thus the genus is polybasic. Achene morphology of all the species studied has been drawn and described for the first time. Gaillardia pulchella an introduced plant is reported in Nigeria for the first time.