522 CYPERACE^. (sedge FAMILY.) 



long, dark brown ; scales smooth, rigid, rounded ; nut obovate, acute, slightly 

 furrowed and pitted. (Scirpus castaneus, iWt'cAx. S. ferrugineus, £//.) — Salt 

 marshes, Florida, and northward. Aug. - Oct. 



Var. puberula. (Scirpus puberulus, iJ7ic^a-.) Culms single, slender (1° - 

 2° high) ; leaves filiform, involute, and, like the spikes, densely pubescent and 

 somewhat hoary ; nut round-obovate, obtuse. — Low pine barrens. 



2. F. laxa, Vahl. Annual; culms (6'- 18' high) slender, and, like the 

 narrowly linear leaves, often pubescent ; umbel mostly simple ; involucre 2-4- 

 leaved ; spikes oblong-ovate ; scales orbicular, mucronate ; nut obovate, strongly 

 fun-owed and pitted, warty on the edges. (Scirpus sulcatijs, Ell.) — Low 

 grounds, in fields and waste places, Florida to North Carolina. Aug. and Sept. 

 — Umbel occasionally reduced to a single spike. 



* * Spikes clustered, sessile. 



3. F. congesta, Torr. Annual; culms densely tufted (3' -6' high), bris- 

 tle-like, like the rough leaves ; spikes 5 - 10 in a terminal cluster, oblong or cylin- 

 drical, pale, or at length yellowish brown ; involucre 4-leaved, erect-spreading, 

 longer than the culm; scales lanceolate, tapering into a slender spreading point; 

 nut oblong-obovate, crossed with faint lines. — Banks of the Apalachicola River, 

 Florida, and westward. Aug. and Sept. — Spikes 2" - 3" long. 



11. TRICHELOSTYLIS, Lestib. 



Spikes terete, many-flowered. Scales imbricated in few (4-8) rows. Peri- 

 anth none. Style 3-cleft, tumid at the base, deciduous. Nut 3-angled. — Culms 

 jointless, leafy at the base. Spikes umbelled. 



1. T. autumnalis. Culms slender, flat, 2-edged, 6'- 12' high, tufted ; 

 involucre 2-leavcd, mostly shorter than the simple compound or decompound 

 umbel ; spikes linear-lanceolate ; scales ovate-lanceolate, mucronate, imbricated 

 in 4 rows ; stamens 2 ; nut white, obovate, obtuse, often warty. (Scirpus autum- 

 nalis, Z.) — Low grounds, Florida to Mississippi, and northward, very common. 

 July - Oct. ® 



12. ISOLEPIS, R. Brown. 



Spikes few - many-flowered. Scales imbricated in few - several rows. Peri- 

 anth none. Style 3-cleft, the tumid base persistent at the apex of the 3-angled 

 nut. — All annuals (in our species), with filifonn or bristle-form culms and 

 leaves. Spikes umbelled or clustered. Leaves j-adical. 



* Spikes umbelled. {Smles pubescent.) 

 1. I. capillaris, R. & S. Culm (4' -6' high) smooth, furrowed, and, like 

 the rough-edged leaves, bristle-like ; spikes 3 - 4, in a simple umbel, oblong, 6-8- 

 flowered ; scales oblong, obtuse, strongly keeled, brown on the sides, imbricated 

 in 4 rows; nut obovate, obtuse, nearly equal-sided, transversely wrinkled ; sta- 

 mens 2. (Scirpus capillaris, L.) — Moist sandy places, Florida, and northward. 

 June - Sept. — Sheaths of the leaves bearded at the throat. Involucre 2-3- 

 leaved, scarcely longer than the umbel. 



