DISPERSAL OF SEED PLANTS BY BRANCHES 437 



depend largely upon propagating by the roots to keep up 

 their numbers. 1 



411. Dispersal of seed plants by branches. There is a shrub 

 of the honeysuckle family, 2 common in the northern woods, 

 which is quite generally known as hobblebush, or witch-hobble, 

 and sometimes as trip-toe. This is because the branches take 

 root at the end and so form loops which catch the foot of the 

 passer-by. The same habit of growth is ^^ 

 found in the raspberry bush (Fig. 336), in 

 one species of strawberry bush (Euonymus), 

 and in some other shrubs. 

 Many herbs, like the 

 strawberry plant and the 

 cinquefoil, send out long 

 leafless runners which 

 root at intervals and so 

 propagate the plant, carry- 

 ing the younger individ- 

 uals off to a considerable 

 distance from the parent. 



Living branches may 

 drop freely from the tree and then take root and grow, after 

 having been blown, or carried by a brook or river, to a favor- 

 able spot, perhaps hundreds of yards away. The so-called snap 

 willows lose many live twigs under conditions suitable for start- 

 ing new trees. 



A slightly different mode of dispersal from that of the rasp- 

 berry is one in which buds separate from the plant and serve 

 to propagate it. In the bladderwort (Fig. 337), at the close of 

 the growing season, the terminal buds are released by the decay 

 of the stem and sink to the bottom of the water in which the 

 plants live, there to remain dormant until spring. Then each 

 bud starts into life and gives rise to a new individual. 



1 See Beal, Seed Dispersal, Chapters n and in. 

 a Viburnum alnifolium. 



FIG. 337. A free branch and two buds 

 of bladderwort 



After Beal 



