HY DROCHARIDE 133 
FH], Morsus-Rane, L., Frog-bit; an aquatic plant with 
floating leaves; Southern Switzerland, Pyrenees, rare. 
2. VALLIGRERIA, L. 
Dicecious ; male flowers small, on short stalks; female 
flowers on long stalks which coil up before and after 
flowering ; both enclosed in spathes; leaves all radical, 
very long, grass-like; ovary unilocular; styles 3. 
V. spiralis, L.; Lake Lugano. The contrivance for fer- 
tilisation in this plant is very remarkable. The very long 
stalk of the female flower is coiled up till the flower is 
mature, when it uncoils, bringing the flower to the sur- 
face. At the same time the male flowers mature, break 
off from their flower-stalk, rise to the surface, and dis- 
charge their pollen, which floats to the stigmas of the 
female flowers. After pollination has been effected, the 
stalk of the female flower again coils up, bringing it below 
the surface to ripen its seeds. 
Elodea canadensis, Mich. (Anacharis Alsinastrum, 
Bab.), the Canadian Water-Weed, is naturalised in the 
Swiss lakes and throughout Europe. 
Order LXXXV.—ORCHIDE. 
Flowers bisexual, irregular; sepals 3, usually nearly 
alike, coloured; petals 3, the lower one or lip usually 
larger and often spurred; stamens I-2, confluent with 
the style; pollen generally collected into a pollinium in 
each anther-cell; ovary inferior, I-celled; stigma sessile ; 
ovules minute, very numerous, on three parietal placentee ; 
