Chromosome morphology has been described in 20 species of Anemone s. lat. (Anemone s. str. 15 species, Pulsatilla 3, Hepatica 2). Two series, one based on 8 chromosomes and the other on 7, are present, in each of which two patterns can be recognized when an orderly arrangement of the chromosomes has been made. In the 8-chromosome series, the distinctions are based on differences in the arm ratio of chromosome IV, namely ratios of about 1:2 versus 1:1.4–1.8. Species in the first group include A. palmata, 2n = 16; A. parviflora, 2n = 16; A. caroliniana, 2n = 16; A. silvestris, 2n = 16; A. virginiana–riparia–cylindrica complex, (all 2n = 16); A. quinquefolia, 2n = 32; and species in the second group are A. pavonina, 2n = 16; A. coronaria, 2n = 16; A. hupehensis, 2n = 16; A. rivularis, 2n = 16; A. rupicola, 2n = 16; Pulsatilla pratensis, 2n = 16; P. nuttalliana ssp., 2n = 16; and P. occidentalis, 2n = 16. A. multifida, 2n = 32, has one chromosome set in each of the above groups. The 7-chromosome series falls into two groups on the basis of a combination of characters. Group one: long arms of chromosome I shorter than those of the longest chromosomes, long arms of chromosome II longer than those of the third pair, and arm ratios in chromosome II of 1.4–1.6. Group two: long arms of chromosome I longer than those of all others, long arms of chromosome II shorter than any of the others, arm ratios in chromosome II < 1:1.4. Species in the first group are Anemone canadensis, 2n = 14; A. richardsonii, 2n = 14; and A. fasciculata, 2n = 14; and in the second group, Hepatica americana, 2n = 14; and H. acutiloba, 2n = 14. Anemone multifida and A. quinquefolia are recognized as allotetraploids. The cytological results are discussed in relation to current classification.
PRECOCIOUS MEIOTIC CENTROMERE SEPARATION OF A NOVEL YEAST CHROMOSOME