Genus 12. 



SEDGE FAMILY 



1. Dichromena colorata (L.) Hitchcock. 

 Narrow-leaved Dichromena. Fig. 839. 



Schoenus coloratus L. Sp. PI. 43. 1753. 

 D. leucocephala Michx. Fl. Bor. Am. 1 : 37. 1803. 

 Dichromena colorata A. S. Hitchc. Ann. Rep. Mo. 

 Bot. Gard. 4: 141. 1893. 



Glabrous, culm slender, erect, rather sharply 

 triangular, i c -2° tall. Leaves distant, narrowly 

 linear, about 1" wide, much shorter than the 

 culm, those of the involucre 4-6, reflexed when 

 mature, yellowish-white at the base; head glo- 

 bose, 6"-io" in diameter; spikelets narrowly 

 oblong, acute; scales membranous, lanceolate, 

 nearly white, i-nerved, subacute at the apex; 

 achene obovate, brown, papillose or wrinkled 

 transversely, nearly truncate at the summit, com- 

 pressed, covered by the truncate-based tubercle. 



In moist sandy soil, New Jersey to Florida and 

 Texas. Bermuda ; tropical America. June-Sept. 



2. Dichromena latifolia Baldw. Broad- 

 leaved Dichromena. Fig. 840. 



Dichromena latifolia Baldw. ; Ell. Bot. S. C. & 

 Ga. 1 : 90. 1816. 



Culm stout, obtusely triangular or nearly 

 terete, the leaves lanceolate or linear-lanceo- 

 late, tapering gradually to a long-acuminate 

 apex from a broad base, i4"-4" wide, some- 

 times overtopping the culm, but the lowest 

 much shorter, those of the involucre 7-10, 

 strongly reflexed when old. Head globose, 

 6"-9" in diameter; spikelets oblong, subacute; 

 scales ovate-lanceolate, nearly white, rather 

 obtuse; achene nearly orbicular in outline, pale 

 brown, faintly wrinkled transversely and lon- 

 gitudinally, so as to appear reticulated ; tu- 

 bercle decurrent on the margins of the achene. 



In wet pine barrens, Virginia to Florida and 

 Texas. June-Aug. 



13. 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, l-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, widely distributed, most abundant in warm regions. Besides the following, 

 some 35 occur in the southern United States. Type species : Rynchospora aurea Vahl. Beak-sedge. 



Style entire or 2-toothed, persistent as a long-exserted subulate beak. 1. R. corniculata. 

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



Bristles minute or wanting. 2. R. pallida. 



Bristles plumose. 3. R. oligantha. 

 Bristles downwardly barbed or rarely smooth. 



Scales white or nearly so ; bristles 9-15- 4. R- alba. 

 Scales brown ; bristles 6. 



Leaves filiform ; achene oblong. 5. R. capillacea. 

 Leaves narrowly linear, flat ; achene obovate. 



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

 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. glomeraia. 



Spikelets very numerous in 2-6 very dense globose heads. 8. R. axillaris. 

 Bristles upwardly barbed. 



Spikelets numerous in 2-6 very dense globose heads. 8. R. axillaris. 



