11(10). Base of culms bulbous, often joined together into a stout knotty rhi- 

 zome; old leaf bases often persisting as shreddy remnants; outer 



surface of fertile scales usually with some puberulcnce 



10. F. puberula. 



11. Base of culms rarely bulbous, usually producing fascicles of slender orangish 

 rhizomes; old leaf bases not persisting as shreddy remnants; outer 



surface of fertile scales seldom with any puberulence 



11. F. puberula var. interior. 



1. Fimbristylis autumnalis (L.) R. & S. Fig. 208. 



Cespitose annual, usually 5-20 cm. tall; leaves glabrous, spreading, subdis- 

 tichous, from half as long as the culms to equaling the culms; blades linear (to 

 4 mm. broad), flat, the backs with numerous raised veins, the margin a pale 

 cartilaginous ciliate-scabrid border; sheaths broader, keeled, with a broad scarious 

 tan entire margin, joining the blade at an acute angle or truncate; ligule present 

 as a line of short pale hairs; scapes flat, similar to the leaf blades, the edges often 

 harsh; longest involucral bract with blade similar to that of the leaves, seemingly 

 a continuation of the scape, shorter to longer than the inflorescence; spikelets 

 linear-oblong to lanceolate, usually 3-7 mm. long, pale- to dark-brown, in an 

 open to densely paniculate system of cymes, the primary rays usually ascending; 

 fertile scales ovate-lanceolate, usually keeled, entire, the midrib excurrent as a 

 mucro; stamens usually 2, rarely 1, 0.2-0.3 mm. long; style 3-branched, much 

 longer than the achene, trigonous at the base, subterete above toward the branches, 

 entirely smooth; achene trigonous-obovoid, apiculate, about 1 mm. long, pale- 

 brown, the surface smooth to quite verrucose. 



Moist to wet sands, peats, silts or clays, primarily of disturbed sunny ground, 

 in marshes, and mud and water at edge of streams, ponds and lakes, in Okla. 

 (Mayes, Ottawa, Love, Mcintosh, LeFlore, McCurtain and Sequoyah cos.) and 

 most of Tex.; various provinces of e. N.A.; Carib., I., Mex. and C.A.; also Old 

 and New World trop. 



2. Fimbristylis miliacea (L.) Vahl. Fig. 209. 



Cespitose annual to 5 dm. tall (rarely to 1 m.); leaves equitant, distichous, from 

 one half the length of the plant to nearly as long, rigid, smooth, flabellately spread- 

 ing, tapering evenly from broad clasping sheaths into the blade, thence continuing 

 to taper into a slender tip, the numerous veins raised and evenly spaced; margin 

 of the blade narrow, pale, cartilaginous, antrorsely ciliate-scabrid, the margin of the 

 sheath somewhat broader, scarious and entire; sheaths keeled, often bladeless; 

 ligule not evident; scapes slender but rigid, flattened or somewhat angled in cross 

 section toward the base, more flattened distally but often with a double margin 

 along each edge; spikelets subglobose to ovoid or short-cylindrical, 2-4 mm. long, 

 on flattened scabrous pedicels in a compound loose to congested system of cymes; 

 longest involucral bract usually shorter than the inflorescence; fertile scales ovate, 

 pale- to (usually) dark-brown, smooth, the apex obtuse to rounded or emarginate, 

 the margin entire, the midrib paler by contrast or greenish and rarely excurrent; 

 stamens 1 or 2, the anthers less than 1 mm. long; style 3-branched, the unbranched 

 portion not much longer than the achene, subterete below, more flattened and 

 fimbriate above toward the branches; achene obovoid (usually narrowly so), apic- 

 ulate, about 1 mm. long, pale-brown, reticulate, the cells narrowly rectangular and 

 horizontally oriented in 4 to 6 rows on a face, the longitudinal ribs usually more 

 prominent and usually verrucose. 



Sandy peat, peat-muck and silt of open areas such as savannahs, pond, lake or 

 river shores, cult, areas (particularly rice fields), in the U.S. from N.C. s. in the 

 Coastal Plain into peninsular Fla., w. along the Gulf Coast into Tex.; throughout 

 the Carib. I., Mex. and C.A. 



405 



