246 SEEDLINGS OF AQUATICS [ch. 



later roots borne on the hypocotyl and plumule are negatively 

 geotropic. 



An exceptional case is that of Littorella lacustris^^ in which 

 the seeds remain in situ. The gynaecea are borne close to the 

 axis, between the leaves, near the base of the little plant. On 



Fig. 159. Zannichellia polycarpa , Nolte. A, L.S. fruit (x 15) ; a = stigma; h = coty- 

 ledon; h = hypocotyl; k = vascular tissue; r primary root; p = plumule. 

 B, cotyledon emerging from fruit (x 6). C, seedling (x 4); rh root hairs. 



[Raunkiaer, C. (1896).] 



the death of the parent, the fruits are left surrounded by the 

 decaying remains; they germinate where they were produced, 

 only being dislodged in rare instances. The somewhat similar 

 behaviour of Cymodocea aequorea has been discussed on p. 127. 



1 Fauth, A. (1903). 



