1928] Wexelsen: Chromosome Numbers and Morphology in- Trifolium 365 



Chromosome Individuality 



Karpechenko (1925) states that he finds no chromosome indi- 

 viduality in the species examined by him. In contrast to this the 

 species reported upon here exhibit many dififerences in chromosome 

 size and shape within the haploid sets. The most striking of these 

 is the presence of satellites attached to the chromosomes. In five 



7; (^A '«? V 



^-^i iC^-i^ O-TC 



Fig. 3. Variations in chromosome size in T. repens. Somatic metapliase 

 figures from root tips of: a, var. gigantemn, plant no. 13a; b, var. sylvestre, 

 plant no. la ; c and d, of plants lb and Ic of the same variety ; e, and /, from 

 Fi of the cross la x 13a. Stained with Haidenhain 's haematoxylin. 



American species, representing three sections of the genus ; and in 

 four European species, also from three sections, there is 1 pair of 

 satellited chromosomes. In one species, Trifolium minus, there are 

 probably 3 pairs; in T. repens 1 pair of satellited chromosomes was 

 seen in one plate only (fig. 3a.). Although large, the satellites in 

 Trifolium are often difficult to observe, because the chromosomes have 

 a tendency to stick together end to end, and in the same way the 

 satellites will stick to the end of the mother chromosome. This may 



