Genetic Systems II i 197 



dual breeding system. This usually is not referred to as apomixis, 

 except where it assumes the entire reproductive function during a 

 portion of the life cycle. Ordinarily, as in some species of Viola 

 (violets), sexual reproduction and asexual reproduction occur at 

 the same time (Fig. 9.7). For example, individual plants of Viola 

 produce runners or stolons at the base; these eventually produce a 

 series of new rosettes which may become separated from the parent 

 plant. Typical violet flowers also occur; they are pollinated by in- 

 sects, producing heterozygous seeds. At the same time, however, 

 cleistogamous flowers may be formed. These flowers, close to the 



Fig. 9.7 I Violet (Viola) showing typical flowers, cleistogamous flowers, 

 and vegetative propagation (creeping underground steins). 



