VALLISNERIACEi^-TAPE-GRASS 



FAMILY 



EEL-GRASS. TAPE-GRASS 



Vallisneria spiralis 



Named for Antonio Vallisneri, 1661-1730, an Italian 

 naturalist. 



A submerged perennial, rooted in sand or mud, with 

 long grass-like, floating leaves; common in sluggish 

 streams and shallow lakes; well known because it twists 

 its long, tough leaves around oar-blades and boat-rudders. 

 Of wide distribution both in America and in Europe. 

 August-September. 



Leaves. — Three to six feet long, thin, narrowly linear, 

 three to five-nerved, obtuse, sometimes serrate near the 

 apex. 



Flowers. — Dioecious, that is, the stamens and pistils 

 grow on separate plants. The staminate flowers develop 

 under water, surrounded by a spathe and borne on a 

 short scape. They are clustered on a short receptacle; 

 perianth three-parted; stamens generally two. The 

 bud of staminate flowers separates from the scape at the 

 time of flowering, rises to the surface and expands there, 

 so that the stamens float with the drift of the surface 

 water. 



The pistillate flowers are borne upon a long, slender 

 scape that curves more or less spirally; the spathe is 

 half an inch to an inch long, enclosing a single white flower. 

 The perianth tube is three-lobed. Ovary is as long as 

 the spathe; stigmas three. 



After the stigma receives the pollen from the floating 



to 



