CTPKRACE.B. (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, (i) (F. Baldwiniana, Ton. F. brizoides, Nees, &c.) Low, mostly 

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



2. TRICHEL6STYLIS, Lestib. Styk 3-deft: achenium triangular: other- 

 wise nearly as in $ 1. 



3. F. autumnal is, Rccm. & 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. (Scirpus autumnalis, L.) Low grounds, 

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



$ 3. ONC6STYLIS, Martins. Style 3-cleJl, 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. (J) (Scirpus, L.) Sandy fields, &c., common, especially south* 

 ward. Aug. - Sept. 



9. FUIRENA, Rottboll. UMBRELLA-GBASS. . 



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

 Scales imbricated in many ranks, awned below the apex, all florifcrous. 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. Achenmm 

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

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



1. F. quarr6a, 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. ptiMiLA, Torr. is a dwarf form, l'-6' high, with 2-6 

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

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

 mostly the small variety. Aug. 



1O. PSIL.OCARYA, 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 i/a\os, bare, and 

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



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

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



