Rhynchospora. 



CYPERACEyE. 



363 



Tribe V. RHYNCHOSPOREjE. Nees. 



Flowers perfect or polygamous. Spikelets mostly fevj -flowered. Scales irregularly im- 

 bricated, obscurely distichous or trifarious. Perigynium usually of several (rough or 

 plumose) bristles, rarely wanting. Achenium conspicuously beaked with the persistent 

 base of the style, or crowned with an articulated tubercle, often corrugated or sculptured. 



11. RHYNCHOSPORA. Vahl, enum. 2. p. 229; Gray, mon. Rhynch. in ann. lyc. N. 



York, 3. p. 193, and in Torr. Cyp. I. c. 4. p. 363. BEAK-RUSH. 



[ Prom the Greek, rhynchos, a beak, and spora, seed.] 



Spikelets mostly few-flowered. Scales loosely imbricated : the lowermost smaller and empty; 

 1 - 3 of the others being of perfect flower ; the remainder being staminate or empty. 

 Perigynium composed of 6 (rarely 10 - 12) plumose or rough bristles. Stamens 3 (rarely 

 2, 6 or 12). Style 2-cleft. Achenium crustaceous, biconvex or nearly globose, smooth or 

 transversely wrinkled, crowned with the dilated persistent and distinct base of the style. — 

 Culms more or less triangular, simple, leafy. Inflorescence terminal and axillary, corymbose, 

 paniculate or fascicled, loosely or densely clustered. 



* Eurhynchospora. Nut lenticular, or more or less compressed. Bristles of tlie perigynium naked, rough or hispid. 



1. Rhynchospora alba, Vahl. White Beak-rush. 



Culm triquetrous above; spikelets corymbose -fasciculate (whitish); bristles usually 10, 

 retrorsely hispid ; achenium smooth, ovoid-lenticular, narrowed at the base, shorter than the 

 bristles. — Vahl. enum. 2. p. 236 (var. a.); Pursh, fl. 1. p. 49 ; Ell. sk. 1. p. 57 ; Torr. fl. 

 1. p. 54 ; Gray, Rhynch. I. c. no. 24, and in Torr- Cyp. p. 366 ; Beck, bot. p. 428 ; Dar- 

 lingt.fl. Cest.p. 24 ; Kunth, enum. 2. p. 295. Schcenus albus, Linn. sp. 1. p. 51 ; Michx. 

 fl. 1. p. 5 ; Bigel. fl. Bost. p. 17. 



Culm slender, 12-18 inches high, smooth. Leaves setaceous, shorter than the culm. 

 Spikelets about 2-flowered, in terminal and axillary clusters, white when young, but becoming 

 brownish with age. Scales lanceolate. Bristles 9-11, with rather long erect hairs near the 

 base, retrorsely hispid above, about as long as the achenium including the tubercle. Stamens 

 mostly 2. Achenium biconvex, a little longer than the slender rostrate tubercle. 



Sphagnous swamps : common. Fl. July - August. Fr. August - September. This differs 

 in no respect from the European R. alba. 



2. Rhynchospora capillacea, Torr. Small Capillary Beak-rush. 



Culm triangular, slender ; spikelets 3-6, mostly in 2 remote clusters ; achenium smooth, 

 oblong-ovoid, compressed, about half the length of the retrorsely hispid bristles, and twice as 



46* 



