194 CYPERACEAE 



achenes plump-lenticular, orbicular-obovoid, pale, 0.5-0.8 mm. long, reticulated, pinched 

 at the base, each with a depressed sessile tubercle. 



In moist pine lands, South Carolina to Florida. Also in the Bahamas and the West Indies. Spring 

 and summer. 



7. Rynchospora Chapmanii M. A. Curtis. Perennial, pale green. Stems densely 

 tufted, 2-6 dm. tall, filiform : leaves resembling the stem but more slender : spikelets ag- 

 gregated into a solitary terminal cluster 1-1.5 cm. broad, spindle-shaped, 3-4 mm. long, 

 whitish, 1-flowered : scales 5, acuminate or awn-tipped, the upper one fertile : perianth- 

 bristles wanting: achenes lenticular, oval, barely 1.5 mm. long, smooth and shining, each 

 with a depressed-deltoid tubercle 3-^ as long as the achene. 



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



8. Rynchospora pallida M. A. Curtis. Rootstocks slender: stems triangular, 3-6 

 dm. tall : leaves various, the lower reduced to scales ; blades 1-2.5 mm. wide, nearly 

 smooth : spikelets numerous, spindle-shaped, 4-6 mm. long, aggregated in a compound 

 terminal head, or occasionally also in a cluster from the upper axil : bracts with subulate 

 blades : scales pale greenish brown, lanceolate, acuminate : perianth-bristles minute and 

 early deciduous, or wanting : stigmas 2 : achenes lenticular, obovoid-oblong, smooth, brown, 

 shin-ing, 2 mm. long, or nearly so, each with a minute depressed tubercle. 



In pine-land bogs, New Jersey to North Carolina. Summer and fall. 



9. Rynchospora oligantha A. Gray. Rootstocks short : stems almost thread-like, 

 leafy toward the base, 1.5-4 dm. tall: leaves few; blades filiform: spikelets solitary or 

 2-4 together, terminal, narrowly oblong, acute, 6-8 mm. long, subtended by 1 or 2 filiform 

 bracts : scales ovate, pale brown, acute, cuspidate : perianth-bristles usually 6, densely 

 plumose below the middle : stigmas 2 : achenes obovoid, 2 mm. long or nearly so, obtuse, 

 pale brown, dull, transversely wrinkled ; tubercle with a flat depressed border and a 

 flattened conic acute projection. 



In wet sandy soil, Delaware to Florida and Texas. Summer. 



10. Rynchospora plumosa Ell. Perennial, bright green. Stems tufted, 1.5-3.5 

 dm. tall, slender and wiry : leaves few ; blades filiform, curving in age : spikelets oblong- 

 ovoid, 2.5-3.5 mm. long, in 3 or 4 lax clusters at the top of the stem : scales broadly ovate 

 or oval : perianth-bristles 6, plumose nearly or quite to the top : achenes orbicular-obovoid, 

 nearly 2 mm. long, including the depressed conic glabrous tubercle, strongly wrinkled. 



In dry pine lands, South Carolina to Flo rida and Louisiana. Spring to fall. 



11. Rynchospora intermedia (Chapm. ) Britton. Perennial, bright green. Stems 

 tufted, 3-7 dm. tall, stout : leaves numerous at the base of the stem ; blades 1-2 mm. 

 broad, more or less involute, with roughish margins : spikelets 3-4 mm. long, in 4-6 

 clusters, forming a more or less interrupted terminal spike-like inflorescence : perianth- 

 bristles plumose nearly or quite to the top : achenes obovoid, transversely wrinkled, more 

 or less grooved, fully 2 mm. long ; tubercle depressed, conic, pubescent. [JS. plumosa var. 

 intermedia Chapm.] 



In pine lands, Florida. Spring to fall. 



12. Rynchospora semiplumosa A. Gray. Perennial, bright green. Stems tufted, 

 2.5-7 dm. tall, rather rigid : leaves rather numerous at the base of the stem ; blades 

 1.5-2.5 mm. wide, often with roughish margins : spikelets crowded into a solitary terminal 

 head, or with an additional cluster farther down the stem : perianth-bristles plumose below 

 the middle or only near the base : achenes globose-obovoid, wrinkled, 1.5 mm. long ; tuber- 

 cle broadly conic, glabrous. 



In pine lands, Georgia and Florida to Louisiana and Texas. Spring to fall. 



13. Rynchospora alba (L. ^ Vahl. Pale green. Rootstocks short: stems slender 

 or filiform, glabrous, 1.5-5 dm. tall : leaves bristle-like or slender, 0.5-1 mm. wide, shorter 

 than the stem : spikelets in 1-4 dense corymbose clusters, narrowly oblong, acute at both 

 ends, 4-6 mm. long : scales ovate or ovate-lanceolate, Avhite or pale green, acute : perianth- 

 bristles 9-15, downwardly barbed, slender, about as long as the achene and tubercle : 

 achenes obovoid-oblong, fully 1.5 mm. long, smooth, pale brown, lenticular ; tubercle lan- 

 ceolate, flat, J as long as the achene. 



In bogs, Newfoundland to Alaska, Florida, Kentucky, Minnesota and Oregon. Also in northern 

 Europe and Asia. Summer. A variety ranging from Georgia and Florida to Texas, with stouter stems, 

 15-24 bristles and clusters of spikelets sometimes 3 cm. broad, is R. atba macro Clarke. 



14. Rynchospora glomerata ( L. ) Vahl. Deep green. Rootstocks slender: stems 

 smooth, 3-10 dm. high : leaves shorter than the stem ; blades flat, 2-4 mm. wide, rough- 

 margined : spikelets in 3-7 corymbose-capitate axillary clusters, oblong, narrowed at both 

 ends, 3-4 mm. long : scales lanceolate, dark brown : perianth-bristles 6, downwardly 



