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slender, the inner ones 10 to 18 mm. long, outermost moderately shorter and thicker: 
awns 3 or 4, sometimes only 2. 
5. B. procera Don. Erect and tall, glabrous: lobes of the narrow leaves linear: 
heads broader, corymbosely paniculate: outer involucre small and inconspicuous: 
rays oval, comparatively large and deep yellow: outer achenes narrowly cuneate- 
oblong and only 4 mm.long; innermost 6 mm. long and cuneate-linear: awns 2, 
strongly barbed, one-half or one-third as long asthe achene. (B, faniculifolia Gray, 
Pl. Wright.)—A species of Arizona and Mexico, reported from Gillespie County 
(Jermy). 
74. COSMOS Cay. 
Like Bidens, except that the rays are purple or rose color (sometimes 
white), and the achenes slender and beaked. 
1. C. bipinnatus Cav. Leaves pinnately divided into narrowly linear or almost 
filiform lobes: heads very showy, the deep rose-colored rays commonly 2.5 cm, or 
more long: achenes smooth and glabrous throughout, with abrupt beak very much 
shorter than body: awns 1 to 3, short.—A Mexican species, represented in southern 
Texas, near Marfa, by the introduced var. EXARISTATUS DC., in which the awns are 
wholly wanting. 
2. C. parviflorus HBK. Slender: heads smaller, with either white or rose-colored 
ays 6 to 12 mm. long: beak of achenes slender, usually half as long as body, scab- 
rous, 2 or 3 (even 4) -awned; otherwise like the preceding. (C. bipinnatus, var. par- 
viflorus Gray, Pl. Wright.) Extreme southwestern Texas. 
75. HETEROSPERMUM Cav. 
Small mainly glabrous branching annuals, with opposite pinnately 
or ternately dissected or sometimes undivided leaves, small rather few- 
flowered heads of yellow flowers, fertile rays, and dimorphous achenes 
(the outer with winged or callous margin, mostly cymbiform; inner nar- 
rower, attenuate upward, marginless; these and sometimes the outer 
with two retrosely barbed awns). 
1. H. pinnatum Cav. Leaves pinnately 3 to 7-parted into linear divisions, which 
are either all entire or some of them again 2 or 3-parted: heads slender-peduncled, 
about 6 mm. high: outer involucre of 3 to 5 linear foliaceous bracts overtopping the 
thin and oval striate inner bracts. (H. tagelinum Gray, Pl. Fendl. & Pl. Wright.)— 
Extreme southwestern Texas, 
76. THELESPERMA. Less. 
Perennial glabrous herbs, with opposite usually finely dissected leaves, 
pedunculate many-flowered heads, yellow neutral rays or none, double 
involucre (the inner connate to the middle and scarious-margined), flat 
receptacle with white-scarious deciduous chaff, nearly terete wingless 
and beakless achenes, and pappus of 2 stout subulate retrorsely hispid 
awns (sometimes obsolete or wanting). 
* Lobes of disk-corollas linear or lanceolate, longer than the short campanulate throat: 
pappus evident, 
1, T. filifolium Gray. Loosely branching and leafy: leaves not rigid, bipinnately 
divided into filiform lobes no wider than the rhachis: bracts of outer involucre 8, 
subulate-linear, equaling or more than half as long as the inner which are connate 
