SUNFLOWER FAMILY. 543 



heads | in. high, in a terminal corj'mbose panicle; chaffy bracts of 

 the receptacle obtusef bracts of the involucre lanceolate, tapering 

 into long spreading tail-like tips; rays about 15 to 20, 1 in. long or 

 more; achenes flattish, glabrous; pappus of 2 or 3 lanceolate chaffy 

 palese. 



Stream beds and banks: Coast Ranges (Howell Mountain, Vaca 

 Valley, Suisun Marshes, Alameda, San Jose); Sierra Nevada. Sept. 



60. HELIANTHELLA T. & G. 



Low nearly acaulescent perennial herbs. Leaves entire, chiefly 

 radical, the cauline mostly opposite. Flowers yellow. Heads 

 large, solitary, long-peduncled. Involucre hemispherical, its bracts 

 linear-lanceolate and loosely imbricated, the outer mostly foliaceous 

 and attenuate-acuminate, the innermost shorter and chaff-like. 

 Receptacle flat or convex, its bracts embracing the achenes. Achenes 

 commonly compressed, with thin or margined edges and emarginate 

 summit. Pappus an awn or chaffy tooth from each margin, and 

 usually with very small intermediate scales. (Diminutive of 

 Helianthus.) 



1. H. Californica Gray. Stems slender, 1 to 2 ft. high, occasion- 

 ally branched; herbage minutely scabrous; leaves ovate to oblong- 

 lanceolate, tapering into petioles; rays little or not at all longer than 

 the involucre; bracts of receptacle obtuse; achenes obovate, smooth, 

 glabrous and narrowly margined, minutely ciliate when young only 

 near the summit; pappus of two short triangular or subulate teeth, 

 and a crown of minute scales nearly obsolete at maturity. 



Higher mountain ridges: Coast Ranges (Contra Costa, Marin, Napa 

 and Solano Cos. and northward to Mt. Shasta); Sierra Nevada. May. 



H. CASTANBA Greene. Stems less than 1 ft. high, hispid with short 

 spreading hairs; achenes cuneate-obovate, not strongly compressed or 

 thin-edged, dull black at base, chestnut-brown above the middle, the 

 apical notch short and deep. — Mt. Diablo. Fruiting heads not seen 

 by us. 



61. BIDENS L. BtTR Marigold. 

 Herbs (ours annuals), with opposite leaves and yellow flowers. 

 Heads many-flowered; rays 3 to 9, neutral. Involucre double, the 

 outer bracts linear-oblong, foliaceous, the inner elliptic to ovate, 

 membranous. Achenes somewhat flattened parallel with the scales 

 of the involucre or slender and 4-sided, those of the disk crowned 

 with 2, 3, or 4 rigid persistent retrorsely barbed awns. (Latin bidens, 

 2-toothed.) 



Leaves simple; rays 3 to 9, conspicuous; achenes downwardly barbed on 

 the margin; rays showy. 

 Outer Involucre little or not at all surpassing the disk ; rays very showy, 



golden yellow 1. B. chrysanthemoides. 



Outer involucre foliaceous and surpassing the disk; rays usually light 



yellow, smaller . 2. B. cernua. 



Leaves pinnately 3 to 5-divided; rays 1 to 5, inconspicuous; achenes 

 upwardly barbed . . . 3. B. frondosa. 



