236 



even very rare in oilier species; the latter fact is distiiiclly in 

 causal relalionsiiip to their ahundant vegetative propagation. In the 

 species in which this is very scarce — therefore, especially in the 

 species helonging to the ty|)es I) and K, hut also in those of 

 the types C and A — the seed ripens, although perhaps not 

 every year in every locality ; this therefore occurs especially in 

 the following species: — S. groenlandica, tricuspidata, oppo- 

 sitifolia and hieraciifolia, but also in aizoides, Aizoon, Hirculus, 

 flagellaris and nivalis. The species which either do not set 

 seed at all or do so rarely, are those which by bulbils or 

 similar means have an abundant vegetative propagation ; there- 

 fore especially S. cermia, rivularis and stellaris f. comosa. The most 

 interesting species in this connection is S. stellaris with its 

 form comosa (see above pp. 218—220). For the rest, how 

 abundant and common fruit-setting is, e. g. in S. flagellaris, 

 S. Hirculus, and other species, requires to be more fully 

 investigated. 



9.-9.-1909. 



