Further Chromosome Counts in Orobanchaceae

Abstract

IN addition to the chromosome counts for British parasitic plants belonging to the Orobanchaceae already published¹, three new counts have been obtained for foreign species. Orobanche cernua var. desertorum Beck (Indian material) was found to possess a diploid complement of 38, as do other members of the subgenus Osproleon, while O. ramosa L. (German material) was found to have 2n = 24 chromosomes, this being the number which I recorded for O. purpurea Jacq., another member of the sub-genus Trionychon. Cistanche tubulosa Wight (Indian material) was found to have 2n = 40 chromosomes. These three counts were made from meiotic stages in pollen-mother cells. The basic number of x; = 12, which has been found for the two members of the subgenus Trionychon, may be contrasted with x = 19 for the members of the subgenus Osproleon; it might be considered that the cytological evidence is such that the relationship between these subgenera is not so close as morphological features appear to indicate.