223 
+ Outer involucral bracts narrow, all more or less united at base: pappus 2-toothed or 
none: leaves opposite, sessile, 3-cleft, appearing as if whorled. 
7. C. palmata Nutt. Nearly smooth, simple: leaves broadly wedge-shaped, rigid; 
the lobes broadly linear, entire, or the middle one 3-lobed.—Extending from the 
northern plains and prairies to western Texas, 
+ + Bracts mostly distinct, the outer leafy, reflered or spreading: achenes flat, obovate 
or cuneate-oblong, I-nerved on each face, 2-toothed or 2-awned: leaves petiolate, 
usually pinnately 3 to 7-divided, the lobes serrate. 
8. C. involucrata Nutt. Somewhat pubescent or glabrous: leaves all 3 to 7-divided 
or parted; the divisions serrate, incised, or some again cleft: heads radiate, with 
conspicuous golden-yellow rays: outer involucral bracts 12 to 20, mostly exceeding 
the inner, slender and hispid: achenes obovate, very flat, with thin ciliate margins 
and 2 short acute teeth.—Extending into Texas from the Mississippi Valley States. 
9. C. discoidea Torr. & Gray. Glabrous and diffusely branched: leaves ternately 
divided, slender-petioled; leaflets ovate-lanceolate, pointed, coarsely serrate: rays 
none or rarely rudimentary: outer involucral bracts usually 3 to 5, mostly surpass- 
ing the heads: achenes linear-wedge-shaped, bearing a pair of short and stout 
upwardly-barbed awns as long as the corolla.—Wet banks and swamps, extending 
from the Atlantic States into Texas. 
73. BIDENS L. (BUR-MARIGOLD.) 
Annual or perennial herbs, with opposite various leaves, many-flow- 
ered heads, 3 to 8 neutral yellow rays (or none), double involucre (the 
outer commonly large and leafy), flattish receptacle with deciduous 
chaff, and obcompressed or slender and 4-sided achenes crowned with 
2 or more rigid and persistent awns which are downwardly barbed. 
* Achenes flat, not tapering at summit: outer involucre foliaceous and spreading. 
1. B. frondosa L. (COMMON BEGGAR-TICKS, STICK-TIGHT.) Smooth or hairy, 6 
to 18 dm. high: leaves mostly petiolate, 3 to 5-divided; leaflets mostly stalked, lan- 
ceolate, pointed, coarsely-toothed: heads erect, nearly rayless: outer involucre much 
longer than the head, ciliate below: achenes wedge-obovate, 2-awned, ciliate (the 
bristles ascending except near the summit.)—A coarse weed, common every where. 
2. B. chrysanthemoides Michx. (LARGE BUR-MARIGOLD.) Smooth, erect or 
reclining at base, 1.5 to 6 dm. high: leaves sessile, lanceolate, tapering at both ends, 
more or less connate, regularly serrate: outer involucre mostly shorter than the 
showy golden-yellow rays (2.5 cm. long): heads somewhat nodding: achenes 
wedge-shaped, with almost prickly downwardly barbed margins, 2, 3, or 4-awned.— 
Wet grounds, from Canada to South America. 
* * Achenes linear: 4-sided, the inner longer and tapering upward: outerinvolucre seldom 
foliaceous or enlarged : leaves all once to thrice 3 to 5-nately parted or divided into 
oblong or linear ultimate lobes. 
3. B. Bigelovii Gray. Lobes of the leaves linear-oblong, mostly obtuse: heads 
narrow, slender-peduncled: rays inconspicuousand yellowish or none: achenes long 
and slender (at least the central ones much surpassing the involucre); the innermost 
10 to 12 mm. long, 2 or 3-awned; outermost half as long or less, stouter, 2-horned, or 
with a pair of short awns, or even with none.—“‘ Common in the foot-hills of Pre- 
sidio County, and valued by the Mexicans as one of their best tea plants. ‘The leaves 
are collected during the time of inflorescence, parboiled and then dried in the sun, 
when they are ready for use” (Havard). It is more than probable that the most 
nearly allied species, the common and disagreeable weed known as “Spanish 
needles,” occurs in Texas. It is characterized as follows: 
4. B. bipinnata L. Primary and secondary divisions of the leaves rather ovate 
or deltoid-lanceolate in circumscription, and the lobes mostly acute: achenes all 
