300 PLANT-LIFE 



with food reserves. Each " eye " indicates a bud, which 

 under favourable circumstances will develop into a new 

 plant. This plant, by means of its tubers, has a re- 

 markable capacity for vegetative reproduction, which 

 the gardener is not slow to recognize and profit by. 

 The Dahlia of cultivation, in order to provide for the 

 next season, and pass successfully through a resting 

 stage, packs plentiful reserves in some of its roots, which 

 consequently become tuberous. From the tuberous 

 roots new plants emerge. The Lesser Celandine (Ranun- 

 culus ficaria), bearing yellow, buttercup- like flowers early 

 in the season, when it grows in shady places, seldom 

 ripens fruit, but it thrives vegetatively not only by 

 underground tubers, but also by means of tuberous 

 buds, known as bulbils, produced aerially in the axils 

 of the leaves. These bulbils are liberated when the 

 plant withers, and, falling to the ground, develop into 

 new individuals. 



The Canadian Water- Weed [AnacJiaris alsinastrum) 

 has been introduced into Britain, and since its first dis- 

 covery there about the year 1842 has become almost 

 ubiquitous in our ponds and streams. Yet it is not 

 known to produce seed in this country. Its stem is 

 very brittle, and any portion of it furnished with a few 

 leaves is capable of rooting, or even growing in a free 

 floating state. It is a remarkable instance of an intro- 

 duced plant extending tremendously in a short period 

 by purely vegetative means. 



Some aquatic plants avoid being caught in the toils 

 of ice in whiter-time by sinking to the bottom of the 

 water, where the ice does not reach, and where they 

 can enter upon a period of rest with a good degree of 



