VI] 



DUCKWEED SEEDLINGS 



81 



The extreme reduction and specialisation, which charac- 

 terise the Lemnaceae, are united with great vigour and vitality. 

 We have already alluded (p. 77) to a special case of the rapid 

 power of vegetative reproduction shown by Lemna gibba^ and 

 the same capacity characterises other members of the family. 

 Another remarkable trait of the Duckweeds is their power of 



FIG. 52. Lemna trisulca, L. Germination. A , germinating seed with operculum (o) 

 just coming away. B, seedling seen from the side. C, seedling further developed, 

 seen from above, ch = chalaza, c = cotyledon, pi = plumule, / = lateral shoot 

 from plumule, 2 / = secondary lateral shoot, r = radicle. (Enlarged.) [Hegel- 

 maier, F. (1868).] 



living and flourishing in water which is so full of organic im- 

 purities that no other Phanerogams can survive in it. If 

 introduced into water with a bad smell, they will purify it until 

 it is a fit habitation for small animals 1 . 



1 Ludwig, F. in Kirchner, O. von, Loew, E. and Schroter, C. (1908, 

 etc.); see also p. 287. 



