CYPERACEAE. 51 



Eleocharis monticola leviseta Fernald. Stems in dense tufts, 10-25 cm. 

 high; heads lance-ovate to lance-oblong, 6-9 mm. long; scales chestnut-brown 

 with paler margins and midribs, acutish; akenes obovate, the flattish tubercle 

 nearly as broad and about one-fourth as long as the body; scales very short, 

 not barbed. In wet places near the mouth of the St. Joe River, Idaho, 

 Humphrey. 



68. SCIRPUS. 



Annual or perennial ; stems leafy or the leaves reduced to basal 

 sheaths; spikelets terete (in ours), solitary, or in a terminal 

 cluster, when it is subtended by a 1-several-leaved involucre; 

 scales in a spiral, usually all fertile, one or two of the lowest 

 sometimes empty; flowers perfect; perianth of 1-6 bristles, or 

 sometimes none; stamens 2-3; style 2-3-cleft, not swollen at the 

 base; akene triangular, lenticular or planoconvex. 



Spikelet solitary, terminal; plant very small. 5. nanus, 



Spikelets several to many; plants large. 

 Stems terete. 



Akenes 2.5-3 mm. long, the scales one-fourth longer. S. occidentalis. 

 Akenes 2 mm. long, the scales little longer. S. validus. 



Stems 3-angled. 



Involucral leaf solitary, erect. 5. americanus. 



Involucral leaves several, spreading. 



Akenes plano-convex; bristles 4. S. microcarpus. 



Akenes 3-angled; bristles 6. 5. atrovirens. 



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, when present 

 longer than the smooth shining akene. In wet places, near Viola, Idaho. 



Scirpus occidentalis (Wats.) Chase. Western Bulrush or Tule. 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. Common in the shallow water of lake margins. 



Scirpus validus Vahl. Very similar to 5. occidentalis; panicle not so large, 

 its branches 1-6 cm. long; spikelets solitary or in clusters of 2-5, rusty brown, 

 ovoid, 5-10 cm. long; scales almost orbicular, pubescent on the back, mucro- 

 nate. Waitsburg, Homer. Rare in our limits. 



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 wet places especially where somewhat 

 alkaline. 



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 on the margins of ponds and streams. 



