l66 FLORA. 



tardily falling from the axis at maturity ; rachis wingless ; scales ovate, acute or 

 obtuse, pale green, strongly 7-11 -nerved, appressed ; stamens 3 ; [style 3 - cleft ; 

 achene oblong or obovoid, 3 -angled, obtuse, apiculate, dull gray, two-thirds as 

 long as the scale, about twice as long as thick. In dry fields and on hills, N. H. 

 to Ont., Minn, and Neb. south to Fla., Kans., Tex. and No. Mex. June- Aug. 



30. Cyperus Houghtoni Torr. HOUGHTON'S CYPERUS. (I. F. f. 572.) Per- 

 ennial by tuber-like corms; culms very slender, smooth, 0.3-0.6 m. tall. Leaves 

 shorter than the culm, 2 mm. wide or less, smooth, those of involucre 3-5, the 

 longer much exceeding the umbel; umbel simple, 1-5 -rayed, the rays mostly 

 short, their sheaths 2 -toothed; spikelets loosely capitate, linear, compressed, 

 acute, 8-16 mm. long, about 2 mm. wide, 11-15 -flowered, falling away from 

 the axis when mature; scales chestnut-brown, firm, shining, oblong, obtuse, trun- 

 cate, or apiculate, strongly about n -nerved; rachis very narrowly winged; 

 stamens 3; style 3-cleft; achene broadly oblong, less than twice as long as thick, 

 3-angled, brown, apiculate, nearly as long as the scale. In sandy soil, Mass, to 

 Minn., Kans. and Ore. July- Aug. 



31. Cyperus Grayi Torr. GRAY'S CYPERUS. (I. F. f. 573.) Perennial by 

 thick hard oblong or ovoid corms; culms tufted, ascending or reclined, stiff, smooth, 

 very slender, 15-50 cm. long. Leaves shorter than the culm, bright green, 2 mm. 

 wide or less, those of the involucre 4-8; umbel 4-io-rayed, simple, the 

 longer rays 7-10 cm. long; sheaths of the rays truncate or nearly so; spikelets 

 5-10 mm. long, loosely capitate, compressed, linear, rigid, spreading ; scales 

 green, ovate, obtuse or subacute, strongly 13-1 5 -nerved, rather widely spreading 

 when old ; joints of the rachis broadly winged; stamens 3; style 3-cleft; achene 

 oblong or oblong-obovoid, obtuse, apiculate, about two-thirds as long as the scale. 

 In sands of the sea shore and in pine barrens, N. H. to Fla. July-Sept. 



32. Cyperus echinatus (Ell.) Wood. BALDWIN'S CYPERUS. (I. F. f. 574.) 

 Perennial by tuber-like corms; culms slender, smooth, erect, mostly longer than the 

 leaves. Leaves pale green, 3-4 mm. wide, those of the involucre 5-10, the longer 

 usually much exceeding the umbel; umbel, 6-i3-rayed ; the rays filiform, their 

 sheaths short, mucronate; spikelets 4-6 mm. long, linear, flat, capitate in globose 

 heads; scales thin, pale green, appressed, ovate-lanceolate, acute, 9-i3-nerved, 

 with narrow scarious margins; joints of the rachis broadly winged ; stamens 3; 

 style 3-cleft; achene oblong-obovoid, obtuse, one-half as long as the scale, about 

 twice as long as thick. In dry soil, N. Car. to Fla., west to Mo. and Tex. July-Aug. 



2. KYLLINGA Rottb. 



Annual or perennial sedges, with slender triangular culms, leafy below, and 

 with 2 or more leaves at the summit forming an involucre to the strictly sessile, 

 simple or compound, dense head of spikelets. Spikelets numerous, compressed, 

 falling away from the axis of the head at maturity, consisting of only 3 or 4 scales, 

 the i or 2 lower ones small and empty, the middle one fertile, the upper empty or 

 staminate. Joints of the rachis wingless or narrowly winged. Scales 2-ranked, 

 keeled. Perianth none. Stamens 1-3. Style 2-3-cleft, deciduous from the sum- 

 mit of the achene. Achene lenticular or 3-angled. [In honor of Peter Kylling, a 

 Danish botanist of the seventeenth century.] About 20 species, natives of tropical 

 and temperate regions. Besides the following, 2 others occur in the So. U. S. 



I. Kyllinga pumilaMichx. Low KYLLINGA. (I. F. f. 575.) Annual; culms 

 densely tufted, filiform, erect or reclined, 3-40 cm. long, mostly longer than the 

 leaves. Leaves light green, roughish on the margins, usually less than 2 mm. 

 wide, those of the involucre 3-5, elongated, spreading orreflexed; head oblong or 

 ovoid-oblong, 6-8 mm. long, simple or commonly with I or 2 smaller ones at the 

 base; spikelets about 3 mm. long, flat, I -flowered, the 2 empty lower scales more 

 or less persistent on the rachis after the fall of the rest of the spikelet; scales ovate, 

 acuminate or acute, thin, about 7-nerved; stamens 2; style 2-cleft; achene lenticu- 

 lar, obtuse. In moist or wet soil, Va. to Fla., west to 111., Mo., Tex. and Mex. 

 Aug.-Sept. 



3. DULl'CHIUM L. C. Richard. 



A tall perennial sedge, with terete hollow jointed culms, leafy to the top, the 

 lower leaves reduced to sheaths. Spikes axillary, peduncled, simple or compound. 



