84 CYPERACEAE. 



Scirpus nanus Spreng. Densely tufted, the stems flattened and grooved, 

 1-6 cm. high; roots with minute tubers; spikelet ovoid, greenish, bearing 2-4 

 or rarely more florets; scales acutish, the lowest usually larger; bristles when 

 present longer than the smooth shining akene. 



Common on brackish shores, but rarely blooming. 



Scirpus subterminalis Torr. Usually aquatic; stems 30-90 cm. high; 

 bract appearing like a constriction of the stem; bristles 6, barbed, shorter than 

 the akene. 



In mountain ponds, rare. Mount Mark, Vancouver Island, Macoun; 

 Mount Adams, Howell, Suksdorf. 



Scirpus riparius (R. Br.) Spreng. Stems tufted, S-1S cm. high; spikelets 

 oblong-ovate, 3-5 mm. long, pale brown; akenes obovoid, 3-angled, smooth 

 dark-brown, 1 mm. long. 



In marshy places along the seashore. Seattle, Piper; Whidby Island, 

 Gardner. 



Scirpus cespitosus L. Densely tufted, the stems 10-30 cm. high; spikelets 

 oblong-ovate, pale brown, about 4 mm. long; akenes oblong, 3-angled, smooth, 

 brown, exceeded by the 6 smooth bristles. 



Sub-alpine bogs, rare. 



Scirpus occidentalis (Wats.) Chase. Western Bulrush or Tide. Stems 

 1—2 m. high, from stout scaly rootstocks; panicle loose, the suberect slender 

 branches 1-9 cm. long, slender; spikelets mostly in clusters of 2—7, pale brown, 

 subcylindric, 10-20 mm. long; scales oblong-ovate, viscid near the apex, 

 aristate. 



In shallow water along lake margins, very common and abundant. 



Scirpus validus Vahl. Very similar to 5 1 . occidentalis; spikelets ovoid, 

 5-10 mm. long; scales broadly ovate, mucronate, somewhat pubescent; akene 

 obovoid, plano-convex, 2 mm. long. 



Rare in our limits, reported from Vancouver Island, Macoun; common east- 

 ward. 



Scirpus americanus Pers. Stems sharply 3-angled, 20-90 cm. high, from 

 stout elongated rootstocks; leaves 1-4, shorter than the stem, channeled; 

 bract 2-10 cm. long, pointed; spikelets 1-6, ovoid, closely crowded; scales 

 brown, ovate, 2-cleft at apex and often awned; bristles 2-6, shorter than the 

 plano-convex smooth akene. 



In brackish marshes, infrequent. 



Scirpus robustus Pursh. Stems stout, often 1 m. tall; leaves about as 

 long as the stem; spikelets brown, ovoid or oblong-ovoid, acutish, 10-20 mm. 

 long; scales ovate, notched and awned. 



Along the seashore, quite common. 



Scirpus microcarpus Presl. Perennial, the stout stems about 1 m. tall; 

 leaves 8-10 mm. broad, smooth beneath, rough on the margins and upper 

 surface of the midvein, the upper leaf usually exceeding the stem; inflorescence 

 a two to three times compound umbel, the primary rays 3-10 cm. long, unequal; 

 bracts leaf-like, about equalling the inflorescence; spikelets ovoid, numerous, 

 dark green, 3-5 mm. long, in heads of 3-12 or more; scales broadly ovate, 

 acute; stamens 2; styles bifid; bristles 4; nutlet white, oblong-lenticular, very 

 short-beaked. 



Common in wooded swamps. 



100. ERIOPHORUM. Cotton-grass. 



Bog perennials with rootstocks and erect triangular or nearly 

 cylindrical stems; leaves linear or one or two of the upper ones 



