Cytology of Some W. Himalayan Cyperaceae

Abstract

Cytological data of 42 W. Himalayan taxa of Cyperaceae is presented. Nine species, Kyllinga triceps (n=48), Cyperus amabilis (n=19), C. cuspidatus (n=56), C. niveus (n=36), C. procerus (n=52), Scirpus erectus (n=37), Eriophorum comosum (n=26), Carex filicina (n=21) and C. nubigena (n=52) are investigated for the first time. New chromosome numbers have been reported in thirteen species, namely, Kyllinga monocephala (n=62), Pycreus capillaris (n=43), Cyperus compressus (n=48), C. corymbosus (n=54), C. difformis (n=18), C. distans (n=29), C. flavidus (n=8), C. haspan (n=18), C. iria (n=64), C. rotundus (n=48), Fimbristylis diphylla (n=5), Carex melanantha (n=24), and C. stenophylla (n=30). Base numbers x=14 and x=26 have been suggested for the genera Scirpus and Eriophorum respectively. The original base number for the family appears to be x=5, other numbers having been secondarily derived through aneuploidy and/or transverse breakage of chromosomes in genera possessing diffuse centromere. This latter feature may account for the small size of chromosomes in these taxa and also for the disparity in size of chromosomes in the genera constituting the family. The two cytological races in each of the three species Pycreus sanguinolentus (n=24, 25), Eleocharis palustris (n=7, 8), and Fimbristylis dichotoma (n=5, 10) did not show any significant morphological differences from one another except for slight variation in size of the inflorescence, and hence do not merit any different status.