276 CYPERACEAE. 



14. RYNCHOSPORA Vahl, Enum. 2: 229. 1806. 



Leafy sedges, mostly perennial by rootstocks, with erect 3-angled or terete culms, nar- 

 row flat or involute leaves, and ovoid oblong or fusiform, variously clustered spikelets. 

 Scales thin, i-nerved, imbricated all around, usually mucronate by the excurrent midvein, 

 the lower empty. Upper flowers imperfect, the lower perfect. Perianth of 1-20 (mostly 6) 

 upwardly or downwardly barbed or scabrous bristles, wanting in some species (no. 2). Sta- 

 mens commonly 3. Style 2-cleft, 2-toothed or rarely entire. Achene lenticular or swollen, 

 not 3-angled, smooth or transversely wrinkled, capped by the persistent base of the style 

 (tubercle), or in some species by the whole style. [Greek, referring to the beak-like tubercle.] 



About 200 species, of wide geographic distribution, most abundant in warm regions. 

 the following, some 27 others occur in the southern United States. 



Besides 



I. J?. corniculata. 



Style entire or 2-toothed, persistent as a long-exserted subulate beak. 

 Style deeply 2-cleft, only its base persistent as a tubercle. 

 Bristles minute or wanting. 

 Bristles plumose. 



Bristles downwardly barbed or rarely smooth. 

 Scales white or nearly so; bristles 9-15. 

 Scales brown; bristles 6. 



Leaves filiform; achene 'oblong. 



Leaves narrowly linear, flat: achene obovate. 



Bristles equalling the achene ; tubercle one-half as long or less. 6. R. Knieskernii. 



Bristles reaching or exceeding the end of the tubercle, which is as long as the achene. 



Spikelets few-several in numerous rather loose clusters. 7. R. glomerata. 



Spikelets very numerous in 2-6 very dense globose heads. 



Bristles upwardly barbed. 



Spikelets very numerous in 2-6 very dense globose heads. 

 Spikelets few-several in rather loose clusters. 

 Achene smooth. 



Leaves setaceous; achene obovate, shining. 

 Leaves narrowly linear, flat; achene broadly oval, dull. 

 Achene transversely wrinkled. 



Spikelets ovoid, in erect cymose clusters; achene longer than the bristles. 

 Leaves flat; spikelets nearly or quite sessile. n. R. cymosa. 



Leaves involute; spikelets distinctly pedicelled. 12. R. Torres-ana. 



Spikelets spindle-shaped, in drooping panicles; achene shorter than the bristles. 



13. R. ine.vpansa. 



2. R. pallida. 



3. R. oligantha. 



4. R. alba. 



5. R. capillacea. 



8. R. a. trill arts. 

 8. R. a.villaris. 



9. R.fusca. 

 10. R. gracilenia. 



i. Rynchospora corniculata (Lam. ) A. Gray. Homed Rush. (Fig. 648.) 



Sclioenuscorniculatusl^am. Tabl. Encycl. i: 137. 1791. 

 Rhvnchospora corniculata A. Gray, Ann. Lye. X. Y. 3: 

 205- 1835. 



Culm obtusely triangular, stout or rather slender, 

 smooth, 3-7 tall. Leaves flat, broadly linear, 

 6'-i&' long, 3"-8" wide, rough -margined; umbels 

 terminal and axillary, sometimes i broad, usually 

 compound; spikelets spindle-shaped, 4 / '-6 // long 

 in flower, capitate at the ends of the rays and ray- 

 lets; primary rays slender, sometimes 6 / long; 

 scales lanceolate, thin, acute, light brown; bristles 

 about 6, subulate or filiform, rigid, upwardly 

 scabrous, shorter than, equalling or exceed- 

 ing the achene; style subulate, entire or min- 

 utely 2-toothed at the apex, 2-4 times longer 

 than the achene, upwardly scabrous, J^'-i' long, 

 persistent and much exserted beyond the scales 

 when mature; achene obovate, flat on both sides, 

 i'' long, dark brown, smooth, its surface minutely 

 cellular-reticulated. 



In swamps, Delaware to Florida, west to Ohio. Mis 

 souri and Texas. July-Sept. 



Rhynchospora corniculata macrostachya (Torr. ) Britton, Trans. N. Y. Acad. Sci. n: 84. I 

 Rhynchospora mafiostachya Torr. Ann. Lye. N. Y. 3: 206. 1835. 



chuS? a^RS^ 10 ^ ** **" achene ' Ran?e of the ^P 6 ' but extending north to I 



