550 COMPOSITAE (COMPOSITE FAMILY) 



1. Ximenesia encelioides Cav. Ic. 2: 60. pi. 178. 1793 (?). Stems 3-6 dm. 

 high, freely branching, pale and cinereous or sometimes canescent: leaves 

 mostly alternate, and the upper face green, ovate or cordate to deltoid- 

 lanceolate, variously serrate or laciniate-dentate, most with winged petioles, 

 and commonly with auriculate-dilated appendage at base: disk 16-20 mm. in 

 diameter: rays 12, 15-25 mm. long, deeply 3-cleft at summit: achenes obovate, 

 mostly broadly winged and with short awns. Verbesina encelioides. From 

 Montana to Texas and Arizona. 



56. COREOPSIS L. TICKSEED 



Annual or perennial herbs. Heads terminating the peduncle-like branches, 

 the ray-flowers neutral, yellow or parti-colored. Disk-flowers perfect. In- 

 volucres campanulate or hemispheric, the bracts in 2 series, all more or less 

 united at the base, those of the outer series usually narrow and herbaceous, 

 the inner series broad, variously colored, either thin and scarious or with 

 scarious margins. Receptacle flat or slightly convex, chaffy. Achenes flat 

 or more or less convex on the back, oblong to orbicular, winged or wingless. 

 Pappus in ours wanting or minute. 



Leaves once or twice pinnately divided . . . . . . 1. C. tinctoria. 



Leaves simple , 2. C. lanceolata. 



1. Coreopsis tinctoria Nutt. Journ. Acad. Phila. 2: 114. 1821. Glabrous, 

 5-8 dm. high: leaves opposite, and all 1-2-pinnately divided into lanceolate 

 or linear divisions: outer involucre short and close: rays 12-16 mm. long, 

 either yellow with crimson-brown base or nearly all crimson-brown: disk- 

 flowers dark purple or brown: achenes moderately incurved; pappus none or 

 an obscure border. From Colorado and Arizona to the Saskatchewan and 

 Texas. 



2. Coreopsis lanceolata L. Sp. PI. 908. 1753. Low, only 3-5 dm. high, 

 including the long and simple naked peduncles: leaves ordinarily a few pairs, 

 oblong-spatulate to lanceolate or nearly linear, obtuse, thickish, all entire, 

 or rarely 1 or 2 small lateral lobes: rays commonly 25 mm. long and 12 mm. 

 broad, sometimes smaller: pappus very small or obsolete. Mostly to the 

 eastward of our range. 



57. BIDENS L. BUR MARIGOLD. SPANISH NEEDLES. BEGGAR'S TICKS 



Leaves opposite, simple or compound. Heads of mostly yellow flowers 

 solitary or paniculate. Bracts of the involucre distinct, or united only at the 

 common base. Rays neutral, yellow or white, sometimes wanting. Achenes 

 neither winged nor beaked, 2-5-awned; the awns retrorsely hispid. 



Leaves simple. 



Heads radiate . . . . . . . . . 1. B. glaucescens. 



Heads rayless 2. B. comosa. 



Leaves pinnately parted or divided. 

 Achenes flat, obovate or cuneate. 



Leaves narrowly acuminate; heads many, small, the outer bracts 



4-8 3. B. frondosa. 



Leaves acute; heads few, large, the outer bracts 8-16 . . . 4. B. vulgata. 

 Achenes linear-tetragonal; leaf-segments small. 



Leaf-segments linear 5. B. tenuisecta. 



Leaf-segments deltoid or oblong ....... 6. B. bipitmata, 



1. Bidens glaucescens Greene, Pitt. 4: 258. 1901. Stout, often freely and 

 widely branched, 3-8 dm. high, glabrous, the terete stem glaucescent, the in- 

 ternodes short and foliage ample: leaves elliptic-lanceolate, the largest 10-15 

 cm. long, closely striate-nerved between midnerve and margin and as closely 

 serrate: heads large, hemispherical; outer involucre surpassing the rays; these 

 many (occasionally wanting): disk-corollas exceeding the awns, the tube 

 longer than the short cylindric limb: achenes mostly 4-angled and 4-awned, 



