VEGETATIVE PROPAGATION 



219 



repens), and the Common Horsetail (Equisetum arvense) are cases in 

 point. Any node serves to provide new buds ; and as the long under- 

 ground rhizomes are broken 

 up in preparing the soil, this 

 does not eliminate, but tends 

 to spread the weed. 



It thus appears that vege- 

 tative extension and propa- 

 gation of the individual is a 

 very wide-spread feature, both 

 in Flowering Plants and in 

 those lower in the scale. It 

 is effective in wild life, as 

 well as under the hand of the 

 gardener. A very consider- 

 able proportion of the per- 

 ennial plants which we see 

 have been so produced. This 

 applies especially to the 

 Grasses and Sedges, whose 

 perennial rhizomes are con- 

 stantlv growing forward, and 



after cultivation, in heat, on moist soil. 



as constantly rotting pro- 

 gressively from the base. But probably the most prominent, and at. 

 the same time familiar example of all is the Bracken Fern, which covers 

 immense area? all over the w r orld. Its underground rhizomes branch 

 freely ; if a single specimen be dug up, and followed backwards, the 

 brown region of decay is soon reached. Young seedling Brackens 

 are rarely met with in the open. Here then is a case where the apical 

 growth and branching of the individual are practically unlimited, and 

 where its vegetative increase in number of physiologically independent 

 units appears to be unlimited too. It may be held as a type of that 

 vegetative spread and multiplication which, though it involves no 

 special development for the purpose, is frequent among perennial 

 plants. 



FIG. 167. 

 Part of leaf of Gloxinia, bearing adventitious buds 



