Chromosome Number of Cardamine pratensis

Abstract

I NOTICE with interest Dr. Howard‘s records of chromosome counts of 2n = 56 for several plants of Cardamine pratensis growing in damp places¹. I have been working on British plants of this species for the last two years, with the help and guidance of Dr. K. B. Blackburn, and I have collected a very considerable amount of information on its chromosome number. The normal plant which grows in damp meadows has constantly the chromosome number 2n = 56, judged from the evidence of seventy plants collected from eighteen vice-counties. Plants with semi-double flowers, first described by Dr. Wilfred Robinson² in 1925, have been found in fifteen localities in wet places, chiefly in the north of England. They have the same chromosome number 2n = 56. Plants with 2n = 30 chromosomes seem to be characteristically from the south of England. Those examined include five normal plants and seven completely sterile double-flowered plants. No other chromosome numbers than these have so far been encountered.