Frequent in moist or wet sand, often associated with S. koilolepis, e. and s.e. 

 Tex., spring; Ark., La. and Tex. 



11. Scirpus koilolepis (Steud.) Gl. 



Tufted annual: roots fibrous; culms cespitose, 4-22 cm. long, dark-grayish- 

 green, compressed, 0.3-0.35 mm. thick, minutely striate, ascending, often some- 

 what flexuous or arcuate; blades 2-5 cm. long, arcuate-setaceous; bract solitary, 

 appearing as a continuation of (and as thick as) the culm, (13-) 17-33 mm. long; 

 inflorescence of 1 or less commonly 2 spikelets; spikelets 3-7 mm. long, narrowly 

 ovoid, acute, of (7 to) 10 to 14 flowers; scales never purplish or reddish, tardily 

 serially deciduous; lowest scale larger than the rest; second or third scale from 

 the bottom 2-2.5 mm. long, ovate, acuminate, strongly gibbous, arcuate-convex, 

 the midnerve forming a broad grayish-green keel and mucro or apiculus, the 

 sides translucent, membranous, cellular, with 1 to 3 acrodome veins near the keel 

 on each side; perianth bristles absent; style 3-branched; achene globose to globose- 

 oblong, trigonous, basally rounded or shortly stipitate, apically rounded or usually 

 minutely apiculate. 1.3-1.5 mm. long, the 3 angles about equally prominent, the 

 sides flat or slightly convex, surficially brownish, with numerous vertical rows 

 of very minute pits and a thin whitish-waxy-bloom. 



Frequent in moist sandy loam, in bogs about lakes and ponds, depressions and 

 marshes in coastal prairies and seepage areas, in Okla. (Johnston Co.), e., s.e., and 

 n.-cen. Tex., rare in Edwards Plateau (Burnet Co.), spring; Ga., Tenn. and Ala. 

 to Okla. and Tex.; Calif. 



12. Scirpus supinus L. Fig. 180. 



Tufted annual; culms 3-35 cm. long, 0.6-1.8 mm. thick, essentially terete 

 (ridged on drying), not or only obscurely and bluntly trigonous; sheaths somewhat 

 loose, apically oblique and acute, essentially bladeless; lower bract appearing 

 as a continuation of the culm, (1-) 3-10 (-15) cm. long; other bracts much- 

 reduced, very inconspicuous; inflorescence a glomerule of 2 to 8 spikelets or occa- 

 sionally some of these extended on peduncles 1-3 cm. long; spikelets lance-ovate, 

 4-11 mm. long, of 16 to 36 flowers; scales somewhat convex basally, ovate, 

 acuminate, acute, with a very strong keel (green turning stramineous) and sides 

 which are green-membranous turning firm and buff"y to purple; style 2-branched 

 [var. Hallii (Gray) Gray] or 3-branched [var. saximontanus (Fern.) Koyama]; 

 bristles variable; achenes 1.3-1.5 mm. long, glabrous, to broadly elliptic, in tran- 

 section either plano-convex (var. Hallii) or strongly trigonous (var. saximontanus) 

 and surficially with horizontal ridges or wrinkles. 



Frequent in moist areas near the coast and in mud about lakes and ponds, s.e. 

 Tex. and Rio Grande Plains (both varieties), rare in n.-cen. Tex. and Plains 

 Country (var. saximontanus), spring-summer; var. supinus is widespread in temp, 

 parts of the world; var. Hallii in e. U.S. mainly Coastal Plain; var. saximontanus 

 in Great Plains, N.D. to Tex. 



Scirpus "supinus." in the present broad sense, has only recently been treated as 

 several narrowly defined species, of which three are attributed to our area and are 

 characterized as follows: 



S. Wilkensii Schuyler. Styles mostly 2-parted and achenes 2-angled; scales 

 mostly 1.9-2.3 mm. wide, the cells at the upper margin of the ventral surface 2 

 to 5 times as long as wide; spikelet achenes mostly 1-1.2 mm. wide, with narrow 

 acute transverse ridges. 



Ditches, swales and pond margins, s. Tex. (Aransas, Atascosa, Kleberg, Nueces 

 and Willacy cos.) spr.-fall; also Tarn. 



S. saximontanus Fern. Style mostly 3-parted and achenes 3-angled; scales usually 

 longer than wide; spikelet achenes with more than 15 narrow transverse ridges. 



355 



