732 ORDER 155. CYPERACE^E. 



I TRIBK 4. CAEICE^E. Glumes imbricated or alternate. Setm 0. Perianth 

 (perigyniuin) of united scales, sac-like, enclosing the aclieninm. Style 2 or 3- 

 tleft. Flowers diclinous CARES. 17 



1. DULICH'IUM, Rich. (Gr. dvu two, Ae^oy, scale; the glumes 

 are in two rows.) Spikes linear- lanceolate, subcompressed ; glumes 

 sheathing, closely imbricated in 2 rows; style long, bifid, the persistent 

 base crowning the compressed achenium ; ovary invested with 6 to 9 

 barbed seta?. 2 St. leafy. Spikes sessile, alternately arranged in 2- 

 rowed, axillary racemes. 



D. spathaceum Pers. Marshes, borders of streams, U. S. and Can. St. round, 

 leafy, and somewhat 3-sided above, thick, sheathed below. Lvs. alternate, point- 

 ing 3 ways, 2 to 4' by 3''. Sheaths tubular, shorter than the internodes. Clus- 

 ters axillary from within the sheaths, and terminal, each consisting of 8 to 10 

 linear-lanceolate, alternate spikes in 2 rows. Spikes 5 to 7-flowered, nearly an 

 inch in length. Glumes linear-lanceolate. Aug. 



2. CYPE'RUS, L. GALINGALE. SEDGE. (Gr. KVTretpog, the ancient 

 name.) Spikes compressed, distinct, many-flowered ; glumes imbri- 

 cated in 2 opposite rows, nearly all with a flower enclosed ; flowers 

 without seta} ; stamens 3, rarely fewer ; style 3-fid (rarely 2-fid), decid- 

 uous. Mostly Zf. St. simple, leafy at base, mostly triangular, bearing 

 an involucrate, simple or compound head or umbel at top. 



PYCREITS. Style 2-cleft. Achenium lens-shaped. Spikes flat, 10 to 30-flowered. 



Stamens 2 (partly 3 in No. 1) Nos. 13 



Stamens always 8 .... Nos. 4, 5 



CYPERUB. Style 8-cleft. Achenium 3-angled. Spikes flattened or teretish, 5 to 40- 

 flowered, the one lowest glume empty. (*) 



* Culm with many joints, teretish, and with leafless sheaths at base No. 6 



* Culm jointless, triquetrous, and with leaves below, (a) 



a Pair of scales within each glume free, persistent. Heads denso No. 1 



a Pair of scales adnate to the rachis, or wanting, (b) 



b Spikes raeemously arranged ulon<r the rachis. Stamens 3. (c) 



C Spikes 10 to 20-flowered, the clusters 2-rowed NOB. 8, 9 



C Spikes 5 to 7-flowered, the clusters 2-rowed No. 10 



C Spikes 5 to 10-flowered, clusters many-rowed, (d) 



d Spikes terete or tetragonal Nos. 11, 12 



d Spikes flattened, linear or lanceolate Nos. 13 15 



b Spikes capitate on the summit of the rachis. (e) 



e Glumes with recurved points. Stamen 1 only Nos. 16, 17 



e Glumes with erect points. Stanu-n 1 only No. 18 



6 Glumes with erect points. Stamens 3. (f) 



f Umbel simple. Spikes terete, few -flowered No. 19 



Spikes flatfish, C to 10-flowered Nos. 20, 21 



Spikes flat. 12 to 40-flowered No. 22 



f Umbel compound. Spikes G to 33-flowered Nos. 2325 



MAKISOUS. Style 3-cleft. Achenium 3-angled. Spikes teretish, 1 to 4-flowered, in 



dense heads, the 2 lowest glumes empty Nos. 20, 27 



1 C. diandrus Torr. Culms slender, reclining, 4 to 10' high ; umbel contracted, 

 of 2 to 5 short, unequal rays; spikes flat, ovate or oblong, 12 to 24-flowered, ollu- 

 tish, fascicled at the top of the rachis; glumes obtusish, 1-veined, membranous, 

 green on the keel, the sides rust-colored in various shades ; stam. mostly 2 ; sty. 

 2-cleft, exserted ; ach. obovate, dull. Marshy grounds, N. E. to "W. States, com- 

 mon. A handsome Sedge. Scales 5 to 8" long, near 2 wide. Aug. 



/3. CASTANEUS. Scales of a dark chestnut color, shining, coriaceous, closely im- 

 bricated ; styles scarcely exserted. 



7. PAUCIFLORCJS. Spikes very short, 5 to 9-flowered ; glumes chestnut brown, 

 with yellowish margins ; Ivs. linear-setaceous. N. Ohio. 



2 C. Nuttallii Torr. Culms triquetrous, tufted, 4 to 12' high; rays few and 

 short, loese; spikes (2 to 6'' long) linear-lanceolate, flattened, very acute, 10 to 20- 

 Howered ; scales acute, loosely imbricated, j'ellowish-brown ; stam. 2 ; ach. oblong- 

 obovate, obtuse, with a half 2-clefc style. Brackish meadows, Mass, to La. Lvs. 

 mostly shorter than the culms. Invol. of 4 leaves, 2 of them very long. Spikes 

 C to 12'' long, in loose, irregular umbels. Aug. 



