464 
Spreads extensively by means of its small nut-like tubers, and often becomes a pes 
in cultivated grounds. Var. MACROSTACHYS Boeckl. (C. lutescens Torr. & Hook 
Ann. Lyc.), of Florida and Texas (on the Rio Grande), is a stouter taller form (6 to 
dm. high), with larger 30 to 40-flowered spikelets (25 mm. long and 3 mm. wide) 
Var. ANGUSTISPICATUS Britton, reported from near Sabine Pass, has narrowly linea 
spikelets (about 18 mm, long and 2 mm. wide). 
25 C. Hallii Britton. Stem 6 to 9 dm. high: rootstalks scaly: leaves elongated 
involucre of several leaves, one of them elongated far beyond the others and becom 
ing 3 dm. long or more: umbel more or less compound, with 5 or 6 elongated rays anc 
several shorter ones: spikelets linear, 9 to 15-flowered, arranged in loose heads: scale 
ovate, acute, strongly 7 to 9-nerved, dark reddish-brown, with lighter colored mar 
gins and tips: achene linear.—Eastern Texas and valley of the lower Rio Grande 
++ ++ Annual or perennial: roots fibrous, but stems often hard and corm-like at base. 
26. C. strigosus L. Perennial, propagating by corm-like tubers from the base 
stem mostly stout, 3to9dm. high: most of the rays elongated (2.5 to 12.5 em.), their 
sheaths 2-bristled: spikelets 5 to 25-flowered, narrow, acuminate, spreading: scale: 
oblong-lanceolate, several-nerved ; achene linear-oblong.—Throughout eastern North 
America and extending through Texas to California, An exceedingly variable species. 
Dr. Britton distinguishes the following varieties: Var. ROBUSTIOR Kunth, occurring 
with the type, has large elongated 10 to 25-flowered spikelets; var, CAPITATUS 
Boeckl., reported from Texas by Bigelow, has an inflorescence of several capitate 
clusters on short rays; var. coMPositus Britton, reported from near Sabine Pass, has 
a compound umbel, with 4 or 5-flowered spikelets 8 to 12 mm, long; var. GRACILIS 
Britton, of the lower Rio Grande, is a slender form, with leaves shorter than the stem, 
and an umbel of 1 to 8 short rays bearing few linear spreading spikelets; var. ELON- 
Gatus Britton (B. Michaurianus, var. (?%) elongatus Torr.), collected in Texas by 
Drummond, has much elongated rays bearing single capitate clusters, 
27. ©. stenolepis Torr. Stem rather slender, 6 to 9 din. high, longer than the 
leaves, which are very rough on the margins and whitish beneath: umbel of 6 to 9 
rays shorter than the 3 to 6-leaved involucre and their sheaths truncate: spikes 
ovate and compact: spikelets yellowish, linear, acute, compressed, 5 to &-flowered, 
12 to 16 mm. long: scales linear-lanceolate, acute, spreading, 7 to 11-nerved: 
achenes oblong-linear, acute, dull.—Extending from the Gulf States into Texas. 
28. C. setigerus Torr. & Hook. Stem 12 dm. high, acutely triangular, smooth: 
leaves nearly as long, flat, about 6 mm. wide: involucre of 3 much elongated 
leaves: umbel compound, 7 to 9-rayed; primary rays elongated and erect, secondary 
widely spreading: spike-like heads of 12 to 16 spikelets which are lanceolate and 
about 10-flowered: scales lanceolate, mucronulate, appressed, 3-nerved, tinged 
with brownish-red. (Inel. C, lutescens Torr. Mex. Bound. Survey.)—Valley of the 
Rio Grande, from Eagle Pass to New Mexico. 
29. C. refractus Englem. Perennial: stem 3 to 6 dm. high: Tays more or less 
elongated: spikelets very slender, in rather loose heads, divaricate or more or less 
reflexed, 2 to 4-flowered: joints of the rachis winged, enclosing the linear 
triangular achene.—Near Sabine Pass and Brazos Santiago. 
30. C. tetragonus Ell. Stems mostly slender, 3 to 6 dm. high, as long as the 
green rough-edged leaves: involucre many-leaved: umbel of 6 to 12 slender rays 
(7.5 to 12.5 cm, long): spikes cylindrical, loose, those on the longer rays commonly 
compound: spikelets short (4 to 6 mm.), oblong, 4-angled, 4 to 6-flowered, the joints 
of the rachis broadly winged: scales ovate, mucronate, appressed, 9 to 11-nerved.— 
Extending from the Gulf States through Texas into Mexico. 
31. C. dissitiflorus Torr. Stems filiform, 3 to 6 dm, high: leaves narrow-linear 
umbel simple, 3 or 4-rayed: spikelets scattered along the upper portion of the 
slender rays, lanceolate, compressed, acute, 5 to 7-flowered: scales oblong-lanceo- 
late, acute: achene oblong-obovate, compressed triangular.—Extending from the 
Gulf States to the valley of the lower Rio Grande and Mexico. 
