CYPERACEAE. 31 



1. S. nigricans L. Leaf-shoaths dark-brown or almost black at the base; 

 blades erect, rigid, pungent: scapes tufted, 2-6 dm. tall: bracts of the invo- 

 lucre 2, the lower one surpassing the inflorescence : head about 1 em. long, 

 dark chestnut-colored: spikelets flattened, 6-8-flo\vered, narrowed upward: 

 perianth-bristles 6, unequal, somewhat plumose: achenes oval, white and 

 polished, about 2 mm. long. — Everglades, — F. K. {Bah., Cuba.) 



10. MARISCUS [Hall.] Zinn. Caulescent, often large, herbs. Leaves 

 with rough margins. Spikelets oblong to fusiform, few-flowered, variously clus- 

 tered. Scales spiral, the loAver empty, the middle ones mostly subtending im- 

 perfect flowers, the upper with fertile flowers. Perianth none. Style de- 

 ciduous. Achene ovoid or globose, smooth or longitudinally striate, without a 

 tubercle. [Cladiuin P. Br.] 



1. M. jamaicense (Crantz) Britton. Stems 1.5-3 m. high: leaf -blades very gla- 

 brous, 6-20 mm. wide, the margins spinulose-serrulate: umbels several or 

 numerous, decompound, forming a large panicle: spikelets mostly 2-5 together 

 at the ends of the raylets, narrowly ovoid, acute, 4-5 mm. long: achene ovoid, 

 wrinkled, 2 mm. long. [C. effusiim (Sw.) Torr.] — Everglades and limesinks 

 in pinelands and hammocks. — F. K. (Ber., Bali., Cuha, Ant.) — Saw-grass. 



11. REMEREA Aubl. Caulescent herbs. Leaves imbricate: blades nar- 

 row, rigid. Involucre with numerous bracts, the outer spreading. Flowers 

 perfect. Spikelets numerous, capitate, 1-flowered. Scales about 4, imbricate. 

 Perianth wantiug. Style barely enlarged below, the base continuous with the 

 ovary. Achenes 3-angled, tightly enclosed in the inner scales. — Tuft-grass. 



1. R. maritima Aubl. Stems 0.5-3 dm. tall, densely leafy, simple: leaves 

 numerous; blades linear or linear-lanceolate, 2-10 cm. long, attenuate, slightly 

 involute, smooth: bracts of the involucre resembling the leaves: spike 1-1.5 

 cm. long, ovoid, sometimes compound: spikelets 3-5 mm. long: achenes nar- 

 rowly oblong, 2.5-3 mm. long, often curved, apiculate, rather granular. — 

 Coastal sand-dunes. — F. K. {Ant.) 



12. RYNCHOSPORA Vahl. Caulescent herbs. Leaves not imbricate: 

 blades narrow, flat, or involute. Spikelets not capitate, ovoid, oblong, or fusi- 

 form. Scales thin, 1-nerved, imbricate, usually mucronate by the excurrent 

 midvein. Upper flowers imperfect, the lower perfect. Perianth of 1-24 

 (mostly 6) upwardly or downwardly barbed or scabrous bristles, or wanting. 

 Achene lenticular or swollen, not 3-angled, smooth, cancellate or transversely 

 wrinkled, capped with the persistent tubercle. — Beak-rush. 



Stylo long, its branches much shorter than the united lower part. 

 Spikelets in 1-4 dense globular heads : achenes with a slender 



tubercle. ]. R. Tracyl. 



Spikelets in panlcled clusters : achenes with a stout tubercle. 2. R. corniculata. 

 Style short, its branches as long as the united part or longer. 



Perianth-bristles wanting. 3. R. divergens. 



Perianth-bristles present. 



Achene smooth or cancellate, not transverse-wrinkled. 

 Leaf -blades broadly linear, blunt or merely acute : 



achene 1.5 mm. long. 4. R. cUiata. 



Leaf-blades narrowly linear, attenuate : achenes 2.5 



mm. long. 5. R. Orayi. 



Achene transverse-wrinkled. 



Perianth-bristles shorter than the achene. 



Achene 1 mm. long ; tubercle depressed, wider 



than high. G. R. perplexa. 



Achene 1.5 mm. long; tubercle conic, about as 



high as wide. 7. R. cymosa. 



Perianth-bristles about as long as the achene or 

 longer. 



