196 CYPERACEAE 



barbed, much longer than the achene : achenes broadly oval or nearly orbicular, 1.5 mm. 

 to nearly 2 mm. long, dark brown, lenticular, dull, smooth ; tubercle narrowly subulate, 

 flat, widened at the base, pale, smooth, about as long as the achene. 

 In pine-land swamps, New Jersey to Florida and Texas. Summer. 



23. Rynchospora Baldwinii A. Gray. Perennial, bright green. Stems somewhat 

 tufted, stout, 6-12 dm. tall, sharply 3-angled : leaves several or numerous at the base of 

 the stem, commonly over 1 dm. long ; blades 2-7 mm. wide, attenuate, smooth or nearly 

 so, more or less glaucous : spikelets ovoid or elliptic-ovoid, 5-6 mm. long, chestnut-col- 

 ored, aggregated into 1-3 loosely capitate clusters : perianth-bristles 12-14, upwardly 

 barbed, fully as long as the achene : achenes oval or orbicular-oval, minutely granular, 

 fully 2 mm. long, excluding the triangular-conic smooth tubercle. 



In low pine lands, North Carolina to Georgia and Florida. Spring to fall. 



24. Rynchospora fascicularis (Michx.) Vahl. Perennial, light green. Stems 

 sparingly tufted, 6-12 dm. tall, obscurely 3-angled : leaves several at the base of the stem ; 

 blades 1.5-3 mm. broad from a dilated base, or rarely slightly wider, more or less invo- 

 lute : spikelets about 2-3 mm. long, acuminate, lanceolate in outline, aggregated in 2-5 

 remote sometimes compound clusters : perianth-bristles much shorter than the achene, up- 

 wardly barbed : achenes lenticular, oval or orbicular-oval, 2 mm. long excluding the tri- 

 angular smooth much flattened tubercle. 



In low pine lands, South Carolina to Florida and Louisiana. Spring to fall. 



25. Rynchospora brachychaeta Sauv. Perennial, pale green. Stems tufted, very 

 slender or nearly filiform, spreading or procumbent, 2-4 dm. long : leaves several at the 

 base of the stem ; blades involute, thus bristle-like or filiform : spikelets ovoid, about 4-5 

 mm. long, usually few together in a small terminal cluster : perianth-bristles 3-6, upwardly 

 barbed, much shorter than the achene : achenes lenticular, suborbicular, fully 2 mm. long 

 including the triangular tubercle, granular, dark brown, twice or thrice as long as the 

 bristles. 



In low pine lands, North Carolina to Florida. Also in Cuba. Spring to fall. 



26. Rynchospora dodecandra Baldw. Perennial, yellowish green. Stems some- 

 what tufted, 5-12 dm. tall, 3-angled : leaves crowded at the base of the stem ; blades 4-10 

 mm. wide, rather rigid, smooth : spikelets ovoid, 6-8 mm. long, several in 4-6 rather open 

 corymbs : perianth-bristles 6-10, upwardly barbed, shorter than the achene : achenes len- 

 ticular, orbicular-obovoid or oval, smooth, 3-4 mm. long excluding the depressed nipple- 

 like tubercle which is surrounded by a collar-like base, the body barely twice as long as the 

 bristles. \_R. megalocarpa A. Gray. ] 



In dry sand, North Carolina to Florida and Mississippi. Spring to fall. 



27. Rynchospora ciliata (Michx. ) Vahl. Perennial, light green. Stems not densely 

 tufted, 3-8 dm. tall, bluntly 3-arigled, smooth : leaves often numerous at the base of the 

 stem, mostly less than 1 dm. long ; blades broadly linear, 5-8 mm. wide, ciliate, glaucous, 

 blunt or merely acute : spikelets narrowly ovoid or lanceolate in outline, 5-6 mm. long, 

 usually aggregated into a solitary terminal capitate cluster : perianth-bristles 6, | as long 

 as the achene : achenes lenticular, cancellate, oval or orbicular-oval, 1.5 mm. long ; tuber- 

 cle rather depressed, conic. 



In low pine lands, North Carolina to Florida and Mississippi. Spring to fall. 



28. Rynchospora Grayi Kunth. Perennial, light green. Stems often solitary, 

 3-7 dm. tall, relatively slender : leaves several or numerous at the base of the stem ; blades 

 narrowly linear, 1.5-3 mm. long, smooth, attenuate : spikelets ovoid, 5-6 mm. long, light 

 chestnut-colored, aggregated into usually 2-4 capitate clusters : perianth -bristles 6, as long 

 as the achene and tubercle : achenes lenticular, plump, cancellate, obovoid, or broadly ob- 

 long, 2-5 mm. long, dark brown ; tubercle depressed-conic, overtopped by the bristles. 



In dry pine lands, North Carolina to Florida and Texas. Spring to fall. 



29. Rynchospora Plankii Britton. Perennial, bright green. Stems more or less 

 tufted, 1.5-4 dm. tall, slender : leaves mainly basal ; blades narrowly linear, attenuate, 

 1.5-4 mm. wide, smooth, flat or nearly so: spikelets ovoid, 2. 5-3 mm. long, chestnut-colored, 

 acute or acuminate, aggregated into 1 or few clusters : perianth-bristles 6, much shorter 

 than the achene, often about % as long: achenes obovoid or orbicular-obovoid, about 1.5 

 mm. long, cancellate, brown, each surmounted by a depressed tubercle with a collar-like 

 base. 



On plains and prairies, Arkansas and Texas. Spring and summer. 



30. Rynchospora rariflora Ell. Perennial, bright green. Stems densely tufted, 

 2-5 dm. long, sometimes reclining, filiform, smooth : leaves involute-filiform or bristle- 

 like, smooth : spikelets elliptic or ovoid, few in 2 or 3 lax filiform-peduncled corymbs : 

 perianth -bristles 6, fragile, shorter than the achene : achenes lenticular, obovoid or broadly 



