SEDGE FAMILY 105 



green, ovate, acute or acuminate, 9-13-nerved. Sandy soil: Ont. — Mo. — Ivans. 

 — (? N.M.)— S.D.— Sask. Plain. Au-0. 



6. C. Houghtoni Torr. Stem smooth, 3-6 dm. high; leaves 1-2 mm. wide; 

 bracts 3-5, some much exceeding the inflorescence; spikelets loosel> capitate in. 

 1-5-rayed umbels, compressed, acute, 8-15 mm. long, about 2 mm. wide, 11-15- 

 flowered; glumes chestnut brown, shining, oblong, obtuse, strongly 11-nerved. 

 Sandy places: Mass. — Va. — Ark. — w S.D. — Man. Plain. Jl-Au. 



7. C. Bushii Britton. Stem smooth, 3-6 dm. high, longer than the leaves; 

 leaves 3-4 mm. wide, smooth; spikelets capitate in 1-5-rayed umbels, flat, linear, 

 acute, S-15 mm. long; glumes oblong, mucronate, shining, 11-nerved. C. fili- 

 culmis Coult., not Vahl. Sandy soil: Minn. — Mo. — -Tex. — Colo. — Ore. — Wash. 

 Plain. Jl-S. 



8. C. erythrorhizos Muhl. Annual; stems tufted, 0.7-6 dm. high; leaves 

 3-8 mm. wide, rough-margined, the lower equalling or exceeding the stem; 

 bracts 3-7, some 3-5 times as long as the inflorescence; spikelets spicate in 

 mostly compound umbels, linear, subacute, 6-30 mm. long, less than 2 mm. wide, 

 compressed, many-flowered; glumes bright chestnut-brown, oblong-lanceolate, 

 mucronate, appressed. Wet places: Mass. — Fla. — Tex. — Calif. — Wash. Plain. 

 Au-0. 



9. C. strigosus L. Perennial, with a corm-like base, 3-10 dm. high; leaves 

 rough-margined, 4-6 mm. wide; some of the bracts exceeding the inflorescence; 

 spikelets spicate or subcapitate in more or less compound umbels, flat, linear, 

 6-25 mm. long, 2 mm. wide or less, 7-25-flowered ; glumes straw-colored, oblong- 

 lanceolate, several-nerved, appressed; achenes linear-oblong, acute. Moist 

 meadows: Me.— Fla.— Tex.— Calif.— Wash.— wS. D. Plain. Au-0. 



3. RYNCHOSPORA Vahl. Beaked Rush. 



Caulescent perennials, with rootstocks. Spikelets oblong or fusiform; 

 glumes spirally imbricate, the lower empty, usually mucronate or cuspidate by 

 the excurrent midrib. Perianth of 1-24, mostly 6, barbed or scabrous bristles, 

 or rarely wanting. Stamens usually 3. Stigmas 2, rarely wholly united. Achenes 

 lenticular, smooth, cancellate or transversely ■m-inkled. Base of the style per- 

 sistent, forming a tubercle, or the whole style persistent. 



1. R. alba (L.) Vahl. Stems slender, glabrous, 1.5-2.5 dm. high; leaves 

 bristle-like, 0.5-1 mm. wide; spikelets several, in 1-4 dense corymbose heads, 

 narrowly oblong, 4—6 mm. long; glumes ovate or ovate-lanceolate, white, acute; 

 bristles 9-15, equaUing the achenes, which are obovate-oblong, lenticular, pale 

 brown; tubercle triangular, flat. Bogs: Newf. — Fla. — Ky. — Ida. — Calif. — 

 Alaska; Eurasia. Boreal — Mont. Je-Au. 



4. ELEOCHARIS R. Br. Spike-rush, Wire-grass. 



Annual or perennial scapose herbs. Leaves reduced to mere sheaths, or the 

 lower rarely blade-bearing. Scape angled or terete. Spikelets soHtary, terminal, 

 erect. Glumes spirally arranged, imbricate. Perianth of 1-12 bristles, usually 

 retrorsely barbed. Stamens 2-3. Stigmas 2 or 3. Achene lenticular or tri- 

 angular, sometimes obscurely so. Base of the styles persistent on the summit 

 of the achenes, forming a tubercle. 



Style-branches 2; achenes lenticular or biconvex. 



Sheath hyaline, and scarious at the summit. 1. E. thermalis. 



Sheath firm, not scarious at the summit. 

 Annuals, with fibrous roots. 



Achenes black, shining. 2. E. atropurpurea. 



Achenes pale brown, dull. 



Spikelets narrowly oblong or subcylindric ; glumes blimt, closely appressed. 



3. E. Engelmanni. 

 Spikelets lance-ovoid or lance-oblong; glumes acutish, more spreading. 



4. E. monticola. 

 Perennials, with rootstocks. 5. E. palustris. 



Style-branches 3; achenes trigonous or turgid; perennials, with rootstocks. 



Achenes cancellate and longitudinally ribbed; spikelets flat. 6. E. acicularis. 



Achenes smooth, papillose or reticulate. 



