ASEX UAL MUL TI PLICA TION 



35 



the fisherman tears asunder, may give rise to several new in- 

 dividuals. From nine excised fragments of a single Planarian 

 worm, Voigt reared nine individuals (see Weismann, 1904, 

 vol. ii. p. 25). 



Similarly, in regard to plants, many of the simpler multi- 

 cellular forms produce detachable buds, familiar in the case of 

 the liverworts ; and even in the flowering plants the same may 

 occur, as in the bulbils of the tiger-lily. As in animals, great 

 colonies may be formed, consisting of many individuals materially 

 continuous, well seen in strawberries, whose creeping stems root 

 here and there and give rise to independent plants. It is also a 



Fig. 4. — " Comet-form " of Starfish, showing how one arm regenerates 

 the other four. (After Haeckel.) 



familiar fact that cut-off portions of a plant may readily give 

 rise to entire individuals ; a little piece of moss, a Begonia leaf, 

 a corner of a potato tuber — and hundreds of instances might be 

 given— will suffice to start a new plant. In many ways the 

 whole vegetable kingdom seems comparable to the sedentary 

 sections of the class Ccelentera among animals (zoophytes, 

 sea-anemones, corals, etc.), e.g. in the various forms of alternation 

 of generations which occur, and in the readiness with which 

 representative fragments will regrow the whole. This capacity 

 of regenerating the whole from a small piece is the more striking 

 when there is considerable differentiation of tissues and organs, 

 as there is in flowering plants and the higher animals. The 



