232 FLOWERS OF AQUATICS [CH. 



which the long anthers swing on flexible filaments (B in Fig. 

 144, p. 221). In M. spicatum 1 the upper flowers of the spikes 

 are generally staminate, and the lower pistillate, while perfect 

 flowers often occur in the intermediate region. 



Littorella lacustris, which is anemophilous, sets a full com- 

 plement of seeds by this means ; it does not, like Myriophyllum 

 and Hippuris, raise its flowers out of the water, but is sterile 

 except when it grows as a land plant (Fig. 128 C, p. 198). When 

 submerged it develops no flowers, but reproduces itself by 



FIG. 152. Peplis Portula, L. Land form, Forest of Wyre, September 13, 1911. 



A , part of branch. (Nat. size.) B, flower and leaves. (Enlarged.) C, fruit with seeds 



showing through transparent fruit coat. (Enlarged.) [A. A.] 



runners (Fig. 128 y^and B, p. 198). Littorella has been described 

 as flowering so luxuriantly, in the height of summer in a 

 dried-up swamp, that the shaking of the white stamens in the 

 wind gave the whole area a silken sheen 2 , while another record 

 relates to a case of this plant flowering in a dry year, when it had 

 only attained to such minute dimensions that the length of the 

 filaments actually exceeded that of the rest of the plant 3 ! In 

 this genus we are probably not dealing with a case of loss of 



1 Knupp, N. D. (191 1). 2 Buchenau, F. (1859). 



3 Preston, T. A. (1895). 



