Fig. 2. Somatic chromosomes of hybrids between S. bicolor (2n = 2x = 20) and S. angustum (2n = 2x = 10), S. bicolor and S. nitidum (2n = 4x = 20), and S. bicolor and S. macrospermum (2n = 4x = 40). (A) Chromosomes of a hybrid between S. bicolor and S. angustum consisting of five large chromosomes from S. angustum and 10 small chromosomes from S. bicolor. (B) Chromosomes of a S. bicolor x S. nitidum hybrid with 10 large chromosomes from S. nitidum and 10 small chromosomes from S. bicolor. (C) Chromosomes of a S. bicolor x S. macrospermum hybrid with 20 from S. macrospermum and 10 from S. bicolor. The S. bicolor chromosomes are smaller than most of the S. macrospermum chromosomes. Upper arrow shows two chromosomes. Lower arrow shows a chromosome in which the centromere is not fully condensed and appears as a strand. Scale bars = 5 µm.