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. 



A.W. P. 6 



