Cow Lachryma-Jobi lL. Chromosomes of all the popu- 
lations examined, with the exception of one (C-8 in Table 
I), show differential staining into eu- and heteropycnotic 
regions as in the case of C. aquatica. Heteropycnotic 
segments are always present in the proximal regions of 
both arms. In this species also the chromosome arms 
terminate in deep staining chromomeres. In addition, 
terminal as well as intercalary knobs are present. The 
sizes and numbers of knobs vary in the different popu- 
lations. Thus, some populations are devoid of Knobs 
(e.g., population C-4b), while others possess them (e.g., 
eight knobs are present in population C-4a). Detailed 
studies were not performed of knob frequencies in the 
various populations. A complete analysis of the pachy- 
tene chromosome morphology was achieved in one popu- 
lation (C-8), in which the chromosomes do not exhibit 
differential staining (Plate LVII, a, b). An idiogram 
(Plate I,X) was constructed on the basis of average value 
of up to five measurements of lengths and arm ratios for 
sach chromosome (see ‘Table II). The sixth longest 
chromosome of the complement has the nucleolus organ- 
izer inthe long arm in a nearly terminal position (Plate 
ILX). Plate LVIIL illustrates the nucleolus organizing 
chromosome in a population (campus wild) that shows 
differential staining of chromosome regions. 
C. gigantea Koen. Of this species, populations have 
been reported by several investigators (Darlington and 
Janaki Ammal, 1945; Nirodi, 1955; Venkateswarlu and 
Chaganti, 1973) with chromosome numbers of 2n=20 
and 2n=40. The population that we studied (C.G. 1, 
which is native to the mountain range on the west coast 
of peninsular India called the Western Ghats) exhibited 
variation in chromosome numbers ranging from 2n=18 
to 2n=22. One of the plants with 18 chromosomes 
(which at meiosis forms nine bivalents) exhibited well 
tL 21: 
