465 
3*, Spikelets linear and flat, in spicate heads in a compound many-rayed umbel: scales 
reddish or brown, decurrent: stamens 3, 
32. C. giganteus Vahl. Stem triangular, smooth, leafy at base with rigid flat 
eaves: involucre of 8 to 10 leaves equaling the compound many-rayed umbel: 
wimary rays elongated, the secondary ones about 9: spikelets about 12-flowered: 
cales ovate, mucronate, carinate, with reddish back, green keel and whitish 
1yaline margins: achene oblong, concavo-convex, yellowish white. (C. erythrorhizos, 
var. erectus Britton.)—On the lower Rio Grande. 
33. C. erythrorhizos Muhl. Annual: stem 7.5 to 90 cm. high: umbel many- 
‘ayed, with 4 or 5 very long involucral leaves: spikelets very numerous, crowded 
n oblong or cylindrical nearly sessile heads or spikes, bright chestnut-colored: 
cales lanceolate, mucronulate, decurrent upon the rachis as scarious wings which 
oon separate to the base as a pair of free scales: achene triangular.—Apparently 
hroughout the State. 
\ 3. Spikelets narrow, terete or nearly so, few to many-flowered, the scales closely 
appressed, and the broad wings of the jointed rachis inelosing the triangular 
achene.—DICLIDIUM. 
34. C. speciosus Vahl. Stem stout, mostly low (12.5 to 50 em. high): rays of the 
imple or compound umbel mostly all short and crowded: spikelets 10 to 20-flowered, 
-ellowish brown at maturity, the short joints of its axis winged with very broad 
caly margins which embrace the ovate achene: scales ovate, obtusish, imbricately 
yverlapping. (C. Michauxianus Torr., not of Schultes.)—Throughout eastern North 
\merica; reported in Texas as far south and west as Duval County, and probably 
urther west. Var. SQUARROSUS Britton (C. ferruginescens Boeckl.), found in Missouri, 
Texas, and New Mexico, has spreading or recurved reddish scales. Var. PARVUS 
3ritton (C. parvus Backl.), reported by Bockeler from the Drummond collection, is 
ow (2.5 to 7.5 cm.), with a very simple umbel, generally consisting of a single cluster 
yf short terete spikelets. 
35. C. ferox Richard. Stem stout and tall, with broad much elongated involu- 
ral leaves and an open spreading compound umbel: spikelets pale (darker brown in 
3uckley’s specimens), scattered in loose spikes, terete, usually 8 to 10-flowered: 
cales oblong-ovate, obtuse, obscurely 7 to 9-nerved, at length spreading, longer 
han the thick broadly winged joints: achene obovoid-oblong, closely embraced by 
he wings.—From Missouri and Texas (Bigelow and buckley) to Arizona and Cali- 
ornia. 
36. C. oxycarioides Britton. Stem about 6 dm. high, with about six narrow 
longated involucral leaves: inflorescence a single terminal dense globular head 
about 2.5 cm. in diameter) composed of a very great number of sharply acute teret- 
sh about 5-flowered spikelets: scales oblong-ovate, acutish: achene oblong, acute,— 
Valley of the lower Rio Grande. 
4. Spikelets 1 to 4-flowered, subterete, usually in dense heads: scales appressed, several- 
nerved, the lower empty and often persistent afler the fall of the rest of the spike- 
let: joints of rachis winged, inclosing the triangular achene.—MARISCUS. 
* Spikelets 2 to 6-flowered. 
37. C. ovularis Torr. Stem 1.5 to6dm. high: umbel 1 to 6-rayed: spikelets (50 
o 100) very short, blunt, in a globular head, 3-flowered, oblong: scales ovate, 
ybtuse, a littie longer than the ovate-oblong achene.—In the northern Atlantic 
states, southward to Arkansas and the Rio Grande. Var. sPH&RICUS Beeckl., from 
ndian Territory to southwestern Texas, has smaller very dense heads and more 
ubulate reddish brown spikelets, 
