CYPERACEAE 199 



gated, the upper more slender, remote : spikelets fusiform, acute at both ends, about 6 

 mrn. long, numerous in 1-4 narrow finally drooping panicles : scales brown, lanceolate, 

 acuminate : perianth-bristles 6, upwardly hispid, very slender, about twice as long a the 

 achene : achenes linear-oblong or oblanceolate, 2 mm. long, transversely wrinkled ; tuber- 

 cle flat, triangular-subulate, as long as the achene-body, setose. 

 In moist soil, Virginia to Florida and Louisiana. Summer. 



20. SCLERIA Berg. 



Mostly perennial caulescent herbs. Spikelets small, clustered in terminal, or terminal 

 and axillary fascicles, or sometimes interruptedly glomerate-spicate. Flowers monoecious. 

 Fertile spikelets 1-flowered. Staminate spikelets many-flowered. Scales imbricated, the 

 1-3 lower and sometimes also the upper ones of the pistillate spikelets empty. Perianth 

 none. Stamens 1-3. Style slender or sometimes swollen at the base, deciduous. Stigmas 

 3. Ovary supported by a disk (hypogynium), or this wanting. Achenes globose or 

 ovoid, obtuse, crustaceous or bony, white in our species. NUT RUSH. 



Inflorescence of 1 or several terminal or lateral clusters. 



Inflorescence a single terminal cluster : hypogynium wanting. 



Achenes 2-3 mm. long, obtuse, with 2 pits in each side of the 3-angled base. l t S. gracilis. 

 Achenes 4 mm. long, acute, without pits. 2. S. Baldwinii. 



Inflorescence of terminal and axillary clusters. 

 Achene smooth. 



Hypogynium present, 3-angled : leaf-blades 3-9 mm. wide. 



Hypogynium covered with a rough white crust. 3. S. triglomerala. 



Hypogynium supporting 8 or 9 tubercles. 4. S. oligantha. 



Hypogynium wanting : leaf-blades 1.5-2.5 mm. wide. 5. /S. lithosperma. 



Achene reticulated, ridged or papillose. 

 Achene reticulated or irregularly ridged. 



Hypogynium 3-lobed, appressed to the base of the achene. 



Clusters of spikelets sessile or nearly so : achene not hairy. 6. S. reticularis. 



Lower clusters of spikelets filiform-peduncled : achene hairy. 



Achene regularly reticulated 7. S. trichopoda. 



Achene irregularly rugose-reticulated to nearly smooth. 



Clusters of spikelets drooping. 8. S. Torreyana. 



Clusters of spikelets rigid, mostly erect. 9. S. hemitaphra. 



Hypogyniums supporting 6 tubercles arranged in pairs. 10. S. Ciirtissii. 



Achene papillose. 



Hypogynium supporting 3 entire emarginate or 2-lobed tubercles. 



Plant pubescent : bracts very ciliate : achene 3 mm. long. 11. 5. ciliata. 



Plant glabrous throughout : achene 2 mm. long. 12. /S. glabra. 



Hypogynium supporting 6 distinct tubercles. 13. S. pauciflora. 



Inflorescence interruptedly glomerate-spicate. 



Achene with short transverse ridges or somewhat reticulated : plant annual. 14. S. verticillata. 

 Achene smooth : plant perennial. 15. S. hirtella. 



1. Scleria grdcilis Ell. Perennial. Stems tufted, very slender or sometimes filiform, 

 2-4 dm. tall, smooth : leaves few, shorter than the stem ; blades involute, filiform, smooth, 

 simulating the stem : spikelets in a single terminal cluster : scales glabrous : achenes ovoid, 

 2-3 mm. long, obtuse, shining or dull, distinctly ribbed lengthwise, with 2 pits on each 

 side of the triangular base : hypogynium wanting. 



In low pine lands, South Carolina to Florida and Texas. Also in Cuba. Summer. 



2. Scleria Baldwinii Steud. Perennial. Stems relatively stout, 3-10 dm. tall, 

 smooth, at least below, often rough above : leaves few ; blades linear, 2-5 mm. broad, or 

 sometimes narrower, smooth or somewhat scabrous : spikelets in a single terminal cluster : 

 scales glabrous : achenes ovoid, about 4 mm. long, smooth and even, dull, apiculate, ob- 

 scurely triangular, without pits at the triangular base ; hypogynium wanting. 



In pine-land swamps. Florida to Texas. A form with longitudinally ribbed achenes. growing 

 from Georgia and Florida to Texas, is S. Baldwinii costdta Britton. Summer. 



3. Scleria triglomerata Michx. Perennial. Stems 3-angled, 4-10 dm. tall : leaves 

 few, but often conspicuous ; blades flat, glabrous or nearly so, 3-9 mm. wide, the upper at- 

 tenuate, rarely exceeding the stem : flower clusters terminal, and usually also 1 or 2 smaller 

 ones from the axils : achenes ovoid or ovoid-globose, above the hypogynium, obtuse, bony, 

 obscurely 3-angled, smooth, bright white, shining, about 2 mm. high ; hypogynium low, 

 obtusely triangular, papillose-crustaceous. 



In meadows, thickets and dry sand, Vermont to Wisconsin, Florida, Texas and'Kansas. Summer 

 and fall. 



4. Scleria oligantha Michx. Perennial. Stems slender, erect, sharply 3-angled, 

 nearly smooth, 4-9 dm. tall: leaves sometimes numerous in the tufts; blades smooth or 

 slightly rough at the apex, 4-6 mm. wide, the lower short, acute, the upper elongated : 

 clusters terminal, usually also 1 or 2 axillary and filiform-stalked : bracts slightly ciliate 



