STRUCTURE OF MODIFIED SHOOTS 141 



a neglected garden, like Marram -grass on the sandy coast, 

 or Bracken in the woods, each tending to occupy much of 

 the ground to the exclusion of other less-favoured plants. 

 Vegetative increase goes on not only by means of under- 

 ground shoots, but to a very great extent by aerial shoots 

 as well. For example : a plant of Silverweed (Potentilla 

 Anserina) appeared in a garden and was allowed to grow. 

 It soon produced axillary runners like those of the Straw- 

 berry (Fig. 88) , and by the end of the season twelve runners 



Fig. 88. Vegetative Reproduction in the Strawberry. New 

 plantlets arising as axillary shoots on the runners. 



were produced with an aggregate length of seventeen yards, 

 and containing no fewer than 129 rooted plantlets. 



Vivipary. In the case of several Alpine plants, especially 

 in wet autumns, a curious suppression of seed- formation 

 occurs. The embryo, instead of passing through a period 

 of rest in the seed, continues its growth uninterruptedly, 

 and on the inflorescence is borne a number of small plantlets 

 instead of fruits. These eventually drop off and reproduce 

 the plant. Such plants are said to be viviparous (L. vivus 

 = alive, paro = I bring forth) . 



Vivipary occurs also in species of Leek and Garlic, and 

 the young bulb-like plantlets on the inflorescence are called 



