300 



A TEXTBOOK OP BOTANY 



[Ch. VI, 6 



(( 



Fig. 211. — The thallus of a Liver- 

 wort, Marchantia; natural size. 



The cups bear small vegetative gem- 

 mae, of which one is shown enlarged. 

 (From Kerner.) 



leaves little seed-like bodies (Fig. 212), which really are com- 

 pact buds though they separate and give rise to new plants. 

 Similar in nature, albeit very different in ap- 

 pearance, are the little bulblets which so many 

 liliaceous plants produce as 

 outgrowths from their main 

 bulbs. This is a great 

 profit to our gardening, for 

 the possibility of our bulb 

 beds and borders depends 

 upon the existence of these 

 bulblets, which are simply 

 separable buds. 



2. Potential vegetative 

 parts. Some plant parts 

 not specialized for repro- 

 duction can yet serve in- 

 cidentally that function. Thus the brittle twigs of Willows, 

 if blown or drifted to suitable places, take root and grow to 

 new trees. Many kinds of creeping root- 

 stocks, or even roots, will produce new 

 plants when severed, as exemplified by 

 the pertinacious Couch Grass of our gar- 

 dens. The most important phase of such 

 reproduction, however, is found in the 

 power possessed by many plants to strike 

 root from cuttings placed in the ground, 

 whereby they produce full and perfect 

 plants, even though they never reproduce 

 naturally by this method ; and many plants 

 which will not strike root from ordinary 

 cuttings can yet be made to do so by 

 devices well known to skilled gardeners. 

 This potentiality of vegetative reproduc- 

 tion, rarely or never exercised in most of these plants, is 

 rich in consequences for practical gardening. 



Fig. 212. — A 

 seed-like separable 

 bud on the stem 

 of a Lily. (From 

 Bailey.) 



