322 



CYPERACEAE. 



Vol. I. 



6. Fimbristylis geminata (Nees) Kunth. 

 Low Fimbristylis. Fig. 789. 



Trichelostylis geminata Nees, in Mart. Fl. Bras. 2 1 : 



80. 1842. 

 F.Frankii Steud. Syn. PI. Cyp. m. 1855. 

 F. Frankii brachyactis Fernald, Rhodora 11 : 180, 



1909. 



Annual, tufted, glabrous, low, 6'-8' high or 

 less. Culms very slender, compressed ; basal leaves 

 about i" wide, usually shorter than the culms, 

 sometimes equalling them ; involucral bracts 2 

 or 3, not longer than the inflorescence; umbel 

 simple or somewhat compound; spikelets, or 

 most of them, sessile, capitate, or some short- 

 peduncled, or in capitate clusters at the base of 

 the culms, ovoid or oval, 3" long or less ; scales 

 dull, green-brown, ovate, mucronulate; style- 

 branches 3 ; style smooth ; achenes rather larger 

 than in F. autumnalis, distinctly reticulated, some- 

 times granular-tuberculate. 



■ In moist soil, Maine to Ontario, Tennessee and 

 Louisiana. July-Oct. 



7. Fimbristylis autumnalis (L.) R. & S. 

 Slender Fimbristylis. Fig. 790. 



Scirpus autumnalis L. Mant. 2: 180. 1771. 

 Fimbristylis autumnalis R. & S. Syst. 2: 97. 1817. 



Annual, roots fibrous, culms very slender, densely 

 tufted, flat, roughish on the edges or smooth, erect, 

 ascending or spreading, i'-i5' long, usually much 

 exceeding the leaves. Leaves narrowly linear, flat, 

 \"-\" wide, long-acuminate, glabrous, those of the 

 involucre 2-3, usually all shorter than the umbel; 

 umbel compound or decompound (in dwarf forms 

 sometimes reduced to a solitary spikelet), the 

 primary rays \'-\V long, the secondary filiform; 

 spikelets linear-oblong, acute, 2"-$" long, i" thick 

 or less, several-many-flowered ; scales ovate-lanceo- 

 late, appressed, subacute, strongly mucronate, green- 

 ish-brown, the midvein prominent; stamens 1-3; 

 styles 3-cleft; achene obovoid, nearly white, 3-angled 

 with a ridge on each angle, very finely reticulated 

 and sometimes roughened. 



In moist soil, Connecticut to Illinois, Florida and Texas. Also in tropical America. June-Sept. 



6. ERIOPHORUM L. Sp. PI. 52. 1753. 



Bog sedges, perennial by rootstocks, the culms erect, triangular or nearly terete, the 

 leaves linear, or 1 or 2 of the upper ones reduced to bladeless sheaths. Spikelets terminal, 

 solitary, capitate or umbelled, subtended by a i-several-leaved involucre, or naked. Scales 

 spirally imbricated. Flowers perfect. Perianth of 6 or apparently numerous, smooth soft 

 bristles, which are white or brown, straight or crisped, and exserted much beyond the scales 

 at maturity. Stamens 1-3. Style 3-cleft. Achene 3-angled, oblong, ellipsoid or obovoid. 

 [Greek, signifying wool-bearing, referring to the soft bristles.] 



About 15 species, in the northern hemisphere. Besides the following, 1 occurs in Alaska. Type 

 species : Eriophorum vaginatum L. The species are called Cotton-grass or Cotton-rush. 

 Spikelet solitary ; involucral leaf short or none. 



Bristles 6, simple, white, crisped. 1. E. alpinum. 



Bristles 6, each 4-6-cleft, thus appearing numerous. 

 Plants stoloniferous. 



Scales with very narrow pale margins. 2. E. Scheuchzeri. 



Scales with broad pale margins. 3. E. Chamissonis. 



Plants tufted, not stoloniferous. 



Upper sheath inflated ; culm rough at the top. 4. E. callithrix. 



Upper sheath not inflated ; culm smooth. 5. E. opacum. 



Spikelets several, involucrate by 1 or severaljeaves. 

 Leaves triangular-channeled throughout. 



Blade of the upper stem-leaf not longer than the sheath. 6. E. gracile. 



