Chromosome Numbers in Compositae from Pakistan

Abstract

Chromosome numbers of 82 taxa, belonging to 48 genera in ten tribes of the family Compositae, are reported from Pakistan.The chromosome numbers of 13 taxa are reported for the first time, including one new generic count (for Grant ia) and a new base number (x = 10) in Sonchus.The new counts are as follows: n = 6 for Launaea tomentella-, n = 7 for Pulicaria gnaphalodes; n = 8 for Cephalorrhynchus picridiformis; n = 9 for Artemisia salsolioides, Conyza strlcta var.pinnatifida, Grantia aucheri, Heteropappus altaicus var.canescens, Launaea oligocephala, and Phagnalon pycnophyllon; n = 10 for Blumea bovei and Sonchus lacnocephalus; and n = 14 for Scorzonera koelpinioides and Scorzonera tortuosissima.The chromosomal counts for 31 other taxa are new for the flora of Pakistan.Compositae comprise approximately 20,000 species and about 40% of these have been investigated cytologically (Solbrig, 1977).Very little cytological research has been carried out on the family in Pakistan, where to date chromosome number for only 65 (i.e., ca.11.0%) of the ca.