14 SELECTED WESTEEN FLORA 



very common genus, making up a large part of our grass-like marsh 

 plants, but very difficult to determine as to species. The beginner 

 will generally do well to content hitaself with the power to, recognize 

 the genus, and if attempting species should be careful to get fuUy 

 matured specimens. 



1. C. rostrata, Stokes. 



Stems stout, 1-3 ft. high, spongy at the base; leaves long and flat, re- 

 sembling a coarse grass; flowers in spikes, the fertile developing into large, 

 somewhat flask-shaped achenes. Marshes, Man.-Alta. 



2. C. trichoc^rpa, Muhl. 



Stout, 1-3 ft. high, rough, sharp-angled; leaves very rough, often cutting 

 the hands; spikes 2-5, scattered. 



Var. aristUta, Bailey. A common western form, stouter and coarser than 

 the type. Marshes, Man.-AIta. 



XII. LEMNACE.ffi (Duckweed Family). 



femall plants consisting of a leaf-like frond floating freely on the 

 .water, producing one or more small monoecious flowers on its 

 margin, and roots hanging from the lower surface. The smallest 

 flowering plant, often very plentiful, and covering the surface of 

 stagnant water like a green scum. 



1. LEMNA. Duckweed. 

 Flowers usually three together surrounded by a bract. 



1. L. tris^lca, L. 



Fronds produced into a stalk at one end, obscurely 3-nerved, generally 

 several adhering. Stagnant water, Man.-Alta. 



2. L. minor, L. 



Frond ovate, usually separated. Stagnant water, Man.-Alta. 



XIII. JUNCACEiE (Rush Family). 



Grass-like or rush-like plants with very small, regular, perfect, 

 hypogenous flowers. Sepals 3; petals 3; stamens 3 or 6; ovary 

 3-celled, or 1-celled with 3 parietal placentae. A rather curious 

 family with flowers resembling the lily in structure, but the whole 

 plant having the appearance of a sedge. 



