CYPERACEAE (^EUGE FAMILY) 



187 



271. Y. laxa. 



272. F. Yahlii. 



Var. puberula (Miclix.) Britton. Leaves and scapes 

 pubescent. — Ga. and Fla. to Tex.; also n. iu the flat country 

 to Ind., 111., and Mo. 



o. F. laxa Valil. Culms slender (0.5-7 dm. high) from 

 an annual root, ii'eak, grooved and flattish ; leaves linear^ 

 Jiat, ciliate-denticulate, glaucous, sometimes hairy; spike- 

 lets ovoid, acute (0.4-1 cm. long) ; stamen 1 ; 

 achene conspicuously 6-8-ribbed on each side, 

 and with finer cross-lines. — Low ground, near 

 the coast, Pa. to Fla and Tex.; n. in the flat 

 country to 111. and Mo. July-Oct. (Trop. 

 Am.) Fig. 271. 



■»- •(- Spikelets glomerulate ; style glabrous. 



4. F. Vahlii (Lam.) Link. Dicarf tufted annual (0.3-2 dm. 

 high); the culms, leaves and very elongated upright bracts fili- 

 ffjrm ; glomerule 0.3-1 cm. in diameter; spikelets 3-8, sub- 

 cylindric, greenish or pale brown, the narrow scales acuminate ; 



achene minute, transversely reticulate. — Damp sands, 



etc., N". C. to Fla., Tex., and Mo.; iutrod. near Phila. 



July-Oct. Fig. 272. 



* * Style 3-cleft; achene triangular. 



5. F. autumnalis (L.) R. & S. Annual (1-4 dm. 

 high), in tufts; culms flat, slender, diffuse or erect; 

 leaves flat, acute ; umbel compound or decompound, the 

 very numerous slendej'-cylindric to fusiform brown spike- 

 lets 4-10 mm. long; the mucronate-acuminate ovate- 

 lanceolate scales appressed; stamens 1-3; achenes very 



minute, 0.5 mm. long, smooth or 

 minutely roughened. — Low grounds. 

 Pa., 111., and Mo., southw. July- 

 Sept. (Trop. Am.) Fig. 273. 



6. F. Frankii Steud. Similar, 

 0.1-2 dm. high ; the umbel simple or slightly compound 

 (or the spikelets solitary^ in dwarf plants); spikelets ellip- 

 soid or narrowly ovoid, castaneous, the slender tijys of the 

 scales slightly spreading ; achenes 0.75 mm. long. {F. 

 autumnalis Man. ed. 6, in part.) — Sandy shores. Me. to 



273. F. autumnalis. 



274. F. Frankii. Oat., and SOUthw. 



Aug.-Oct. Fig. 274. 



9. SCIRPUS [Tourn.] L. Bulrush or Club Rush 



Spikelets few-many-flowered, solitary or in a terminal cluster when it is sub- 

 tended by a l-several-leaved involucre (this when simple often appearing like a 

 continuation of the culm); the "scales in several ranks, or rarely inclining to be 

 2-ranked. Flowers to all the scales, or to all btit one or two of the lowest, all 

 perfect. Perianth of 1-0 (or 8) bristles, or sometimes wanting. Stamens 2 or 

 3. Style 2-3-cleft, simple, wholly deciduous, or sometimes leaving a tip or 

 point to the lenticular or triangular achene. — Culms sheathed at base. (The 

 Latin name of the bulrush.) 



a. Involucre none, or merely the modified outer caducous scale of the soli, 

 tary terminal small (2.5-7 mm. long) spikelet ; achene trigonous, 

 smooth b. 

 b. Perianth-bristles terete and setulose. 



Scales of the flattened spikelet membranous and awnless ; bristles 

 retrorsely barbed ; achenes beaked. 

 Achene 1 mm. long, constricted below the beak .... 1. 

 Achene 2-2. f> mm. long, the pale beak continuous with the body 2. 

 Scales of the ten-te spikelet with firm green midribs, that of the 

 outermost prolonged into a blunt awn ; bristles setulose M'ith 

 spreading or ascending fine hairs ; achenes beakless. 



S. nanus. 



S. paucijlorus. 



