CYPERACEAE 193 



tf Spikelets 5-10-flowered. 39. R. proltfera. 



** Tubercle not setose. 



Tubercle conic or triangular, acute, %-% as l n g &s the 



achene. 



Achene about 2 mm. long. 40. It. punctata. 



Achene 1-1.25 mm. long. 



Perianth-bristles not longer than the achene or but 



little longer. 



Spikelets clustered : tubercle bluntish. 41. R. microcarpa. 



Spikelets filiform-pedicelled : tubercle sharp- 

 pointed. 42. JR. decurrens. 

 Perianth-bristles as long as the achene and tuber- 

 cle or longer. 43. R. schoenoides. 

 Tubercle depressed, rounded, less than % as long as the 



achene. 44. R. miliacea. 



b. Achene constricted at the base into a stipe : tubercle setose. 45. R. stipitata. 

 B. Spikelets fusiform to lanceolate, 4-6 mm. long. 



Leaf-blades filiform : achene obovoid : tubercle smooth. 46. R. stenophylla. 



Leaf-blades not filiform : achene linear-oblong or oblanceo- 



late : tubercle setose. 47. R. inexpansa. 



1. Rynchospora Tracyi Britton. Perennial, bright green. Stems tufted, 5-12 dm. 

 tall, nearly terete: leaves elongated ; blades channeled, 4-8 mm. wide, straight, erect or 

 ascending: spikelets densely aggregated into 1-6 globose heads 1-2 cm. in diameter, lan- 

 ceolate in outline, 5-6 mm. long, acuminate, pale : scales often 9, the fourth one fer- 

 tile: perianth -bristles 6, very slender: achenes flat, obovoid or cuneate-obovoid, 2.5 

 mm. long excluding the tubercle, minutely wrinkled, ciliate, surpassed by the bristles : 

 tubercle subulate, fully twice as long as the achene. [Ceratoschoenus capitatus Chapm., not 

 B. capitata~R. & S.] 



In pine-land ponds, Georgia and Florida to Mississippi. Spring to fall. 



2. Rynchospora solitaria R. M. Harper. Perennial or perhaps annual, light green. 

 Stems solitary, 6-8 dm. tall, flattened : leaves few ; blades about 2 mm. wide, the lower 

 ones about \ as long as the stem ; upper stem-leaves 1 or 2 : spikelets narrowly lanceolate, 

 5-6 mm. long, 1-flowered, aggregated into a single dense terminal head 12-15 mm. in 

 diameter : bracts filiform, slightly exceeding the inflorescence : perianth-bristles 6, fragile, 

 equalling the achene, upwardly barbed: achenes obovoid, plump, 1.5 mm. long, faintly 

 pitted, not ciliate, capped by a triangular tubercle of about \ its length. 



In moist pine lands, southern Georgia. Summer and fall. 



3. Rynchospora IndianolSnsis Small. Perennial, bright green. Stems 3-angled, 

 5-12 dm. tall : leaves sheathing the base of the stem ; blades 4-8 mm. broad, with smooth 

 margins : spikelets rather numerous, about 1 cm. long, aggregated into several dense 

 panicled clusters 2-3 cm. broad : scales oval, broadly acuminate, deciduous : perianth- 

 bristles surpassing the achene, persistent : achenes flattened and with impressed sides, about 

 4 mm. long, each capped by a tubercle nearly 5 mm. long. 



On damp prairies, Indianola, Texas. Spring. 



4. Rynchospora corniculata (Lam.) A. Gray. Perennial. Stems smooth, 1-2 mm. 

 tall: leaf-blades flat, 1.5-4.5 dm. long, 6-16 mm. wide, rough -margined : umbels some- 

 times 2-5 dm. broad : spikelets spindle-shaped, much over 1 cm. long when mature, 

 clustered at the ends of the rays and raylets : primary rays sometimes 15 cm. long : scales 

 lanceolate, thin, acute, light brown : perianth-bristles about 6, rigid, upwardly scabrous : 

 style subulate from a broad base 2-4 times longer than the achene, upwardly scabrous, 

 1-2.5 cm. long, much exserted beyond the scales when mature : achenes obovoid, flat, 4 mm. 

 long, dark brown, smooth. 



In swamps, Delaware to Florida, Ohio, Missouri and Texas. Summer and fall. A variety with 

 perianth-bristles about twice as long as the achene and congested inflorescence is R. corniculata macro- 

 stdchya (Torr.) Britton ; it extends north as far as Massachusetts. 



5. Rynchospora pusflla M. A. Curtis. Perennial, bright green. Stems densely 

 tufted, 0.5-3 dm. tall, filiform : leaves resembling the stems but more slender and curved : 

 spikelets in 1-3 separate clusters, elliptic-ovoid, about 2 mm. long, often 3-flowered : scales 

 broadly ovate to suborbicular : perianth-bristles wanting : achenes whitish, flat, lenticular, 

 oblong-obovoid or cuneate-obovoid, about 1 mm. long, transversely wrinkled, not pinched 

 at the base, each with an almost free tubercle. 



About pine-land swamps, Florida to Texas. Also in the West Indies. Sp ring and summer. 



6. Rynchospora div6rgens M. A. Curtis. Perennial, bright green. Stems densely 

 tufted, filiform or wiry, 1-4 dm. tall : leaves resembling the stems but more slender, curved : 

 spikelets elliptic to ovoid-elliptic, 3-3.5 mm. long, acute, in loose or rarely somewhat con- 

 tracted corymbs : scales broadly elliptic or broadly ovate : perianth -bristles wanting : 



13 



