BOTANY OF LA SALLE COUNTY. 125 



Jh. S. caly cina. Scape weak, sepals erect. 

 POTOMAGE TON. Pondweed. Stems rooting, leaves 

 2 ranked, alternate, or nearly opposite, round- 

 ovate to linear. 



P. na tans. Leaves long% petioled, elliptical. 



P. flu itans. lonchi tes of Tuckerman. Leaves 

 lon^f, elliptical. 



P. perfolia tus. Leaves roundish. In 111. river. 



P. pauciflo rus. Leaves narrow, linear. 111. R. 



P. pusil lus. Stem slender, flattish. 111. R. 



P. pectina tus. Stem thread-like; leaves very 

 narrow. 111. R. 



Na ias flex ilis. Naiad. Stems slender, leaves nar- 

 row. Slow moving- waters. 



Order 128. CYPERA CEAE. Sedg-es. 



Coarse grass-like plants with solid jointed tri- 

 angular stems; flowers in heads, spikes or 

 umbels . The stems are called culms. 



Cype rus. P. Galling-ale. Umbel rays unequal. 



C. flaves cens. Culms 4 to 10 in.; rays 2 to 4. 



C. dian drus. Rays 2 to 5, very short. 



C. acumina tus. Slender, 3 to 12 in. 



C. filacul mis. Slender, wiry, 8 to 15 in. 



C. strig-o sus. Stout, 1 to 3 ft. 



C. specie sus. 5 to 20 in.; rays crowded. 

 Dulich ium. P. Culm not branched, round, hollow. 



D. spatha ceum. Spikelets flattened, sessile. 

 ELEOCH ARIS. P. Spike Rush. Culms in groups, 



leafless, sheathed at base, each with a single 

 terminal head. 



E. palus tris. Nearly round, striate, 1 to 5 ft. 

 E. ten uis. Hair-like, 4 angfled, 1 ft. 



E. compres sa. In tufts, flat, striate. 



E. acicula ris. Hair-like, 2 to 8 in., angfular. 



