CYPERACEAE 191 



ored ; blades resembling the scapes, half-terete. Spikes in a terminal cluster, 1-8-flowered, 

 subtended by an involucre of 1-2 bracts. Spikelets crowded, often dark-colored : scales 

 imbricated in 2 rows, the lower ones empty, the upper flower-bearing. Perianth of 3-6 

 "scabrous or plumose bristles. Stamens 3. Style barely enlarged at the base, almost wholly 

 deciduous. Stigmas 3. Achene 3-angled, without a tubercle. [Chaetospora R. Br.] 



1. Schoenus nigricans L. Foliage glabrous. Leaves basal ; sheaths dark brown or 

 almost black at the base ; blades overtopped by the scape, erect, rigid, pungent : scapes 

 tufted, 2-6 dm. tall : bracts of the involucre 2, the lower one surpassing the infloreseence : 

 head about 1 cm. long, dark chestnut-colored : spikelets flattened, 6-8-flowered, narrowed 

 upward : scales ovate or lanceolate-ovate, firm, keeled : perianth-bristles 6, unequal, some- 

 what plumose: achenes oval, white and polished, about 2 mm. long, surpassed by the 

 bristles. [Chaetospora nigricans (L. ) Kunth.] 



In damp sandy soil, Florida to Texas and California. Also in the Old World. 



17. CLADIUM P. Br. 



Perennial leafy herbs, similar to the Rynchosporae in habit. Spikelets oblong or fusi- 

 form, few-flowered, variously clustered. Scales imbricated all around, the lower empty, 

 the middle ones mostly subtending imperfect flowers, the upper usually fertile. Perianth 

 none. Stamens 2, or sometimes 3. Style deciduous from the summit of the achene. Stig- 

 mas 2-3. Achene ovoid to globose, smooth or longitudinally striate : tubercle none. 



Leaf-blades about 2 mm. wide : umbels small : achene truncate at the base. 1. C. mariscoides. 



Leaf-blades 6-20 mm. wide : umbels large, panicled : achene narrowed to the base. 2. C. effusum. 



1. Cladium mariscoides (Muhl. ) Torr. Stems 3-9 dm. tall, slender, rather stiff, 

 obscurely 3-angled, smooth : leaves about 2 mm. wide, concave, with long compressed tips, 

 nearly smooth : umbels 2 or 3, compound, small : spikelets oblong, narrowed at both ends, 

 acute, 5 mm. long, capitate on the raylets : scales chestnut-brown, ovate or ovate-lanceo- 

 late, acute ; upper scale subtending a perfect flower with 2 stamens and a filiform style and 

 3 stigmas, the next lower one with 2 stamens and an abortive ovary : achene ovoid, acute, 

 finely longitudinally striate, about 2 mm. long. 



In marshes, Nova Scotia to Minnesota, Florida and Kentucky. POND RUSH. TWIG RUSH. 



2. Cladium effusum (Sw. ) Torr. Stems stout, 1.5-3 m. high, obtusely 3-angled: 

 leaves very long, glabrous, 6-20 mm. wide, the margins spinulose-serrulate : umbels sev- 

 eral 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 ; uppermost scale subtending 

 a perfect flower : stamens 2 : achene ovoid, abruptly sharp-pointed, wrinkled, narrowed to 

 the base, 2 mm. long. 



In water, Virginia to Florida and Texas. Also in the West Indies. SAW-GRASS. 



18. REMIREA Aubl. 



Perennial sometimes caulescent herbs, with horizontal rootstocks. Stems more or less 

 tufted, relatively low. Leaves imbricated : blades narrow, rigid. Involucre with numerous 

 bracts, the outer spreading. Flowers perfect. Spikelets numerous, crowded into a single 

 terminal head, sessile, 1-flowered. Scales about 4, imbricated, the lower one empty. Sta- 

 mens 3. Perianth wanting. Style barely enlarged below, the base continuous with the 

 ovary. Stigmas 3. Achenes 3-angled, tightly enclosed in the inner scales. TUFT-GRASS. 



1. Remirea maritima Aubl. Foliage glabrous, bright green. Stems erect, 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 narrowly oblong, 2.5-3 mm. long, often curved, apiculate, rather granular. 



On sandy beaches, peninsular Florida. Also widely distributed in the tropics. Spring to fall. 



19. RYNCHOSPORA Valil. 



Caulescent herbs, mostly perennial by rootstocks, with 3-angled or terete stems, nar- 

 row, flat, or involute leaf -blades, and ovoid oblong or fusiform, variously clustered spikelets. 

 Scales thin, 1-nerved, imbricated all around, -usually mucronate by the excurrent midvein, 

 the lower empty. Upper flowers imperfect, the lower perfect. Perianth of 1-24 (mostly 

 6) upwardly or downwardly barbed or scabrous bristles, or wanting in some species. 

 Stamens commonly 3. Stigmas 2, rarely wholly united. Achene lenticular or swollen, 

 not 3-angled, smooth, cancel late or transversely wrinkled, capped with the persistent base 

 of the style (tubercle), or in some species by the whole style. BEAK RUSH. 



