212 
1. S. ocymoides DC. Diffusely spreading, hispidulous or hirsute: leaves oval, 
obtuse, abruptly contracted into the petiole: involucral bracts in 2 or 3 series, their 
tips commonly herbaceous: chaff soft or shorter than the flowers: disk commonly 
dark: rays yellow (turning whitish), their achenes mostly triangular and with 3 
slender-subulate diverging awns: disk achenes sometimes 1 or 2-awned,—Along the 
Rio Grande. 
2. S. Aberti Gray. Erect with ascending branches, minutely pubescent or his- 
pidulous, glabrate: leaves lanceolate or nearly linear, narrowed into a margined 
petiole: involucre a single series of dry bracts: chaff conspicuous, with rigid euspi- 
date tips: disk pale: rays white, their achenes almost terete and with 3 very 
short and stout nearly conical awns or tubercles: disk-achenes awnless, or sometimes 
minutely 1-awned.—Southwestern Texas, 
54. TETRAGONOTHECA Dill. 
Erect perennial herbs, with opposite coarsel y-toothed leaves (their 
sessile bases sometimes connate), large single radiate heads of pale 
yellow flowers on terminal peduncles, double involucre (the outer of 4 
large and leafy ovate bracts united below into a 4-angled or winged cup ; 
the inner of small chaffy bracts as many as the ray-flowers and partly 
clasping their achenes), convex or conical receptacle with narrow and 
membranaceous chaff, 4-sided achenes with truncate summit, and pap- 
pus of numerous small chaffy scales or wanting. 
1. T. Texana Gray & Engelm. Minutely pubescent or glabrate: stems slender, 
3to6 dm. high: cauline leaves laciniately pinnatifid or incised, 5 to 7.5 em. long; 
the lower tapering into margined connate petioles; upper with winged petioles or 
bases dilated at insertion and usually connate around the stem into a toothed disk: 
peduncles elongated (10 to 25 cm. long): rays 7 to 9: pappus none, or very minute, 
or sometimes of numerous subulate chaffy scales almost as long as the breadth of the 
achene.—Rocky ground, throughout southern Texas. 
2. T. Ludoviciana Gray. Glabrous or nearly so: stem rather stout, 6 to 12 dm. 
high: leaves ovate or oblong, ample (the larger 10 to 20 em. long), saliently and 
acutely dentate, the lowest on winged petioles, upper all connate by mostly broad 
bases into a large perfoliate disk: peduncles mostly longer than the leaves: rays 10 
to 12: achenes crowned with a conspicuous pappus of rigid oval or oblong chaffy 
scales as long as the breadth of the truncate summit.—Sandy soil, extending from 
Louisiana to western Texas. A depauperate or dwarf form of the southern coast 
of Texas and extending west of San Antonio is var. REPANDA Gray, which flowers 
sometimes from near the ground, the leaves therefore petioled, and the upper with 
perfoliate disk of united bases of the petioles. 
55. SCLEROCARPUS Jacq. 
Strigose-pubescent herbs, with branching stems, alternate or opposite 
leaves, terminal pedunculate radiate heads of yellow flowers, neutral 
ray and fertile disk-flowers, involucre of rather few distinct and more 
or less herbaceous bracts (the outer loose and spreading), convex or 
conical receptacle with its coriaceous or cartilaginous chaff closely 
investing the achenes as a permanent accessory covering, and pappus 
a short crown or ring or none. 
1. S. uniserialis Gray. Annual, 3 to 6 dm. high, loosely branched: leaves all 
alternate, slender-petioled, deltoid- or rhombic-ovate, or uppermost lanceolate, 
