463 
5* Spikelets narrowly linear, in a spreading umbel: scales 3-nerved, decurrent in a per- 
sistent wing: stamens 3: achene round obovate, 
19. C. Haspan L. Perennial by slender running rootstocks: stems 3 to 5 dm. 
high: leaves linear, often reduced to membranous sheaths: umbel spreading, the 
filiform rays mostly longer than the 2-leaved involucre: seales light reddish-brown, 
oblong, mucronate, keeled, decurrent upon the rachis as persistent scarious wings. 
—Throughout the Gulf States and extending throughout Texas to Mexico and 
southward. 
6* Spikelets linear or lanceolate, in large ovate spike-like heads in simple 3 to 5-rayed 
umbels: scales reddish: stamens 3: achene obovate-oblong, pointed. 
20. C. cephalanthus Torr. & Hook, Stem tall (12 dm.), sharply 3-angled, angles 
scabrous: leaves flat (4 mm, wide): involnere of 2 or 3 leaves (one very long, the 
other about as long as the umbel): umbel somewhat simple, 3 or 4-rayed, the large 
ovate spike-like heads with short setaceous involucels: spikelets 50 to 80 in each 
head, linear, about 10-flowered (lowest fasciculate): scales lanceolate, reddish, with 
pale-green keel, remote, pointless, 7-nerved : achene with a short abrupt point.— 
Louisiana and Texas. 
21. C. spectabilis Schreb. Stem 3 to 4 dm. high or more, 3-angled, smooth, from 
a tuberous root: leaves much longer than the stem, acuminate, keeled, with scabrous 
margin: involucre of 3 leaves, one much elongated: umbel of 4 or 5 unequal rays: 
spikelets linear-lanceolate, loosely imbricated, smooth and shining: scales oblong- 
ovate, obtuse, reddish-purple.—Texas (Drummond) and Arizona (Rothrock). 
7* Spikelets slender, in loose or sometimes compact heads in simple or compound umbels: 
seales decurrent in usually persistent scarious wings: stamens 3: achene linear to 
oblong. 
+ Stem jointed, leafless. 
22. CG. articulatus L. Stems stout, 9 to 15 dm, high, from a creeping rootstock 
bearing tuber-like buds: involucre very short, of 3 bract-like pungent leaves: 
umbel compound, many-rayed, spreading or recurved: spikelets long (1 to 3.5 em.), 
linear, spreading, 30 to 40-tlowered, 3 to 10 in a cluster: scales whitish, oblong, 
obtuse, 7-nerved.—Extending from the Gulf States along the coast of Texas. Var. 
CONGLOMERATUS Britton, of the valley of the lower Rio Grande, has spikelets 2.5 
to 87.5 em, long, in dense clusters on the ends of short rays, producing a compact 
glomerate cluster 5 to 7.5 em. in diameter, Dr. Britton also says that ‘‘a form of 
this species with the spikelets greatly elongated has been collected by Mr. Nealley 
in Texas.” 
+ + Stems leafy. 
++ Perennial by tuberiferous stolons, 
283° C. rotundus L. Stem slender, 1.5 to 4.5 dm. high, equalling the leaves: 
umbel simple or slightly compound, about equalling the involucre; the few rays each 
bearing 4 to 9 dark chestnut-purple 12 to 40-flowered acute spikelets 8 to 18 mm. 
long: scales ovate, closely appressed, pointless or nearly so, nerveless except on the 
keel.—From the South Atlantic and Gulf States to the Texan coast (Sabine Pass and 
Brazos Santiago). Often called ‘nut grass, ” 
o4. C. esculentus L. Stem 3 to 7.5 dm. high, equaling the leaves: umbel often 
compound, 4 to 7-rayed, much shorter than the long involucre: spikelets numerous, 
light chestnut or straw-color, acutish, 12 to 30-flowered, 8 to 14 mm. long: scales 
ovate or ovate-oblong, narrowly searious-margined, nerved, the acutish tips rather 
loose: achene oblong-obovate. (C. phymatodes Muhl. OC. repens Ell. )—Throughout 
eastern North America and extending through Texas to Mexico and California. 
