CYPERACEAE 175 



1. Kyllinga pumila Michx. Annual. Leaves light green ; blades roughish on the 

 margins, usually less than 2 mm. wide : scapes densely tufted, filiform, erect or reclined, 

 3-40 cm. long, mostly longer than the leaves : bracts of the involucre 3-5, elongated, 

 spreading or reflexed : head oblong or ovoid-oblong, 6-7 mm. long, simple or commonly 

 with 1 or 2 smaller ones at the base : spikelets about 3 mm. long, flat, 1-flowered, the 2 

 empty lower scales more or less persistent on the rachis after the fall of the rest of the 

 spikelet : scales ovate, acuminate or acute, thin, about 7-nerved : stigmas 2 : achene len- 

 ticular, obtuse. 



In moist or wet soil, Virginia to Illinois, Missouri, Florida, Texas and Mexico. Summer and fall. 



2. Kyllinga brevifolia L. Perennial, pale green. Leaves mostly shorter than the 

 scape ; blades 1-2.5 mm. wide, smooth : scapes very slender or filiform, 1-3 dm. tall, 

 smooth : bracts of the involucre 3, one erect, the others spreading : spikes solitary, globose 

 or ovoid, 5-10 mm. long, greenish, commonly inclined : spikelets oblong-ovoid, 2-3 mm. 

 long, acuminate : scales various, the 2 outer minute, the third and fourth ovate, with re- 

 curved tips and serrulate-ciliate keels : achenes lenticular, orbicular-obovoid, about 1 

 mm. long. 



In low grounds or springy places, Georgia and Florida to Texas. Also in tropical America. 

 Spring to fall. 



3. Kyllinga odorata Vahl. Annual or biennial, pale green. Leaves mostly shorter 

 than the scape ; blades usually 2-4 mm. broad, smooth : scapes tufted, 1-3 dm. tall, 

 smooth : bracts of the involucre 4-5, becoming reflexed : spikes whitish, 1-3, ovoid to 

 cylindric, 8-15 mm. long : spikelets 3 mm. long, oblong-ovoid, 1-flowered or imperfectly 

 2-flowered : scales various, the two lower ones barely \ as long as the ovate smooth third 

 and fourth scale, the fifth enclosed in the fourth scale, larger than the first and second : 

 achenes lenticular, obovoid, fully 1 mm. long. 



In wet soil and along roadsides, Georgia and Florida to Mississippi. Summer and fall. Through- 

 out tropical America. Spring to fall. 



6. ERIOPHORUM L. 



Bog herbs, perennial by rootstocks. Stems erect, triangular or nearly terete. Leaves 

 with linear blades, or 1 or 2 of the upper ones reduced to bladeless sheaths. Spikelets ter- 

 minal, solitary, capitate or in umbels, subtended by an involucre or 1-several bracts, or 

 naked. Scales spirally imbricated, usually all fertile. Flowers perfect. Perianth of 6 or 

 numerous filiform smooth soft bristles, which are white or brown, straight or crisped, and 

 exserted much beyond the scales at maturity. Stamens 1-3. Style deciduous. Stigmas 3. 

 Achene 3-angled, oblong, ellipsoid or obovoid. COTTON-GRASS. 



Spikelets umbellate : achenes obovoid, obtuse. 1. E. polystachyon. 



Spikelets capitate : achenes linear-oblong, acute. 2. E. Virginicum. 



1. Eriophorum polystachyon L. Stems stiff, smooth, obtusely triangular above, 

 49 dm. tall, all the sheaths blade-bearing : leaf-blades flat, 3-8 mm. wide, each tapering 

 to a channeled rigid tip : bracts of the involucre 2-4, the longer ones commonly equalling 

 or exceeding the inflorescence : spikelets 3-12, drooping, in a terminal umbel ; rays fili- 

 form, smooth or rough : scales ovate-lanceolate, acute or acuminate, purple-green or 

 brown : perianth bristles numerous, bright white, about 2.5 cm. long, 4-5 times as long as 

 the scale : achene obovoid, obtuse, light brown. 



In bogs, Newfoundland to Alaska, to New Jersey, the mountains of Georgia, and Nebraska. Also 

 in Europe and Asia. Summer. HAEE'S-TAIL. 



2. Eriophorum Virginicum L. Stems stiff, obtusely triangular above, smooth, 4-11 

 dm. tall, rather leafy : leaf-blades narrowly linear, flat, 2-5 mm. wide, channeled toward 

 the apex : bracts of the involucre 2-4, spreading or deflexed, 5-15 cm. long : spikelets 

 several or numerous in a dense terminal capitate cluster, erect or the outer spreading : 

 scales ovate, acute, brown with a green center, about 5-nerved : perianth bristles numerous, 

 dingy brown, about 3 times as long as the scale : achene linear-oblong, acute, apiculate, 

 light brown. 



In bogs, Newfoundland to Manitoba, Florida and Nebraska. Summer and fall. 



7. FUIRENA Kottb. 



Perennial herbs, with triangular stems and many-flowered terete spikelets in terminal 

 and axillary clusters, or rarely solitary. Scales spirally imbricated, awned, the 1 or 2 

 lower commonly empty. Flowers perfect. Perianth of 3 ovate, oblong or cordate-ovate, 

 stalked, often awned sepals, usually alternating with as many downwardly barbed bristles. 



