80 COMMON CANADIAN WILD PLANTS. 



3. Proserpina' ca. Flowers perfect, the parts in threes. Petals none. 



Stems creeping at the base. Leaves alternate, the immersed ones 

 pinnately dissected. 



4. Calllt'riclie, Flowers monoecious. Calyx and corolla wanting. 



Leaves entire, opposite. Staminate flower of a single stamen ; 

 pistillate flower a single 4-celled ovary. Fruit compressed, 4- 

 lobed. 4-celled, breaking up into 4 one-seeded pieces. 



1. MYKIOPIIYL'U M, Vaill. WATER-MiLFOiL. 



1. M. spiea'tum, L. Stamens 8. Bracts ovate, entire, 

 shorter than the flowers. Leaves in whorls of 3 or 4. 

 Flowers greenish, in terminal spikes. Stems very long. 

 Deep water. 



2. M. vertieilla'tum, L. Stamens 8. Leaves finely dis- 

 sected and whorled as in No. 1. Bracts pectinate-pinnatifid, 

 much longer than the flowers, and the spikes therefore 

 leafy. Stem 2-4 feet long. Stagnant water. 



3. M. heterophyl'lum, Michx. Stamens 4. Lower leaves 

 dissected, in whorls of 4 or 5. Bracts ovate or lanceolate, 

 finely serrate, crowded, the lower ones pinnatifid. Stem 

 stout. Stagnant or slow water. 



4. M. tenel'lum, Bigel. Flowering stems nearly leafless. 

 Bracts small, entire. Flowers alternate, monoecious. 

 Stamens 4. Borders of ponds. 



a. HUT! Kis. L. MARE'S TAIL. 



H. VUlga'riS, L. A perennial aquatic, with jointed erect 

 stem. Muddy margins of ponds and streams. 



3. PROSERPINA'CA, L. MERMAID-WEED. 

 P. palustris, L. (MERMAID- WEED.) Low herb. Stem 

 creeping at base. Leaves alternate, lanceolate, sharply 

 serrate. Petals none. Stamens 3. Fruit nut-like, 3-seeded. 

 Wet swamps. 



4. CALLIT RH HE, L. WATER-STARWOHT. 



1. C. Ver'na, L. Amphibious. Floating leaves obovate, 

 tufted ; submersed leaves linear. Flowers monoecious, 

 axillary, usually between a pair of bracts. Sterile flower a 

 single stamen ; fertile flower a single pistil with a 4-celled 

 ovary. Leaves beset with stellate scales. 



