CYPERACE.E. (SEDGE FAMILY.) 503 



2. F. laxa, Vahl. Culms slender (2'- 12' high), weak, grooved and flat- 

 tish; leaves linear, flat, ciliate-denticulate, glaucous, sometimes hairy; spikes ovate, 

 acute (3" long) ; stamen 1 ; achenium 6-8-ribbed on each side, and with finer cross 

 lines. Q) (F. Baldwiniana, Torr. F. brizoides, Nees, &c.)— Low, mostly 

 clayey soil, Penn. to Illinois, and southward. July- Sept. 



§ 2. TRICHELOSTYLIS, Lestib. — Style 3-cleft: achenium triangular: other- 

 wise nearly as in § 1. 



3. F. autumiialis, Rcem. & Schult. Low (3'- 9' high), in tufts; culms 

 flat, slender, diffuse or erect ; leaves flat, acute ; umbel compound ; spikes ob- 

 long, acute (l"-2" long) single or 2-3 in a cluster; the scales ovate-lanceo- 

 late, mucronate ; stamens 1-3. (J) (Scirpus autumnalis, L.) — Low grounds, 

 Maine to Illinois, and southward. Aug. - Oct. 



$ 3. ONC6STYLIS, Martius. — Style 3-cleft, slender, its small bulb more or less 

 persistent on the apex of the triangular achenium. 



4. F. capillaris. Low, densely tufted (3' -9' high); culm and leaves 

 nearly capillary, the latter all from the base, short ; umbel compound or pani- 

 cled; spikes (2" long) ovoid-oblong; stamens 2 ; achenium minutely wrinkled, 

 very obtuse. ® (Scirpus, L.) — Sandy fields, &c, common, especially south- 

 ward. Aug. - Sept. 



9. FUIRE1VA, Rottboll. Umbrella-Grass. 



Spikes many-flowered, terete, clustered or solitary, axillary and terminal. 

 Scales imbricated in many ranks, awned below the apex, all floriferous. Peri- 

 anth of 3 ovate or heart-shaped petaloid scales, mostly on claws, and usually 

 with as many alternate small bristles. Stamens 3. Style 3-cleft. Achenium 

 triangular, pointed with the persistent base of the style. Culms obtusely angu- 

 lar. (Named for G. Fuiren, a Danish botanist. ) 



1. F. squarrdsa, Michx. Stem (1°- 2° high) leafy; leaves and sheaths 

 hairy; spikes ovoid-oblong (£' long), clustered in heads, bristly with the spread- 

 ing awns of the scales ; perianth-scales ovate, awn-pointed, the interposed bris- 

 tles minute. — Var. pumila, Torr. is a dwarf form, l'-C high, with 2-6 

 spikes ; perianth-scales ovate-lanceolate and oblanccolate. 1J. — Sandy wet 

 places, Massachusetts to Virginia, and southward; also Michigan; northward 

 mostly the small variety. Aug. 



10. PSILOCARYA, Torr. Bald-Rush. 



Spikes ovoid, terete, many-flowered ; the flowers all perfect. Scales imbri- 

 cated in several ranks ; the lower ones empty. Perianth none. Stamens usu- 

 ally 2. Style 2-cleft. Achenium doubly convex, more or less wrinkled trans- 

 versely, crowned with the persistent tubercle or dilated base of the style. — Culms 

 leafy; the spikes in terminal and axillary cymes. (Name from yjsiXos, bare, and 

 Kapva, nut, alluding to the absence of bristles.) 



1. P. SCirpoidcS, Torr. Spikes 20 - 30-flowered ; scales oblong-ovate, 

 acute, chestnut-colored ; achenium obscurely wrinkled, beaked with the sword- 



