ASTERACEAE. 383 



1. L. douglasii DC. Annual, 3 dm, high; leaves mostly basal, 

 2-3-parted into filiform divisions; rays 10-15 cm. long; the ring 

 of the disk-corollas distinctly bearded; achenes sparsely beset with 

 capitate rigid bristles, the margin becoming corky; cup-like ring in 

 place of pappus entire. 



Common on dry plains and in open places in the lower portions 

 of the chaparral belt. March-May. 



2. L. gigantea Kell. Perennial; stems stout, fleshy, 6-20 dm. 

 high, bearing at the summit an ample tuft of leaves and stout 

 peduncles of corymbosely arranged heads; leaves 3-pinnately divided 

 into filiform segments; achenes oblong or ovoid, obscurely 3-5- 

 nerved, narrowly callous-winged; pappus a slight coroniform cup. 



Bluffs along the sea near Santa Monica. Common on the 

 islands. 



34. BIDENS L. 



Annual or perennial herbs with opposite serrate or 

 usually lobed or dissected leaves, or the upper mostly 

 alternate, and usually rather large heads of both tubular 

 and radiate flowers or the rays none. Involucral bracts 

 in 2 series, distinct or somewhat imlted at base, the 

 outer often follaceous and much longer than the inner. 

 Receptacle flat or nearly so, chaffy, the chaff subtending 

 the disk-flowers. Rays when present neutral, usually 

 yellow. Disk-flowers perfect. Achenes flat, quadrangu- 

 lar or nearly terete. Pappus of 2-6 teeth or subulate 

 awns, barbed or hispid. 



1. B. expansa Greene. Aquatic, perennial by stolons, gla- 

 brous throughout; stems erect or ascending, stout, 10-25 dm. high, 

 branched at the nodes; leaves lanceolate, 1-2 dm. long, toothed, 

 narrowed to the connate base; heads on peduncles 4-8 cm. long, 

 erect, nodding in fruit; outer involucral bracts 4-8, foliaceous, 

 reflexed; the inner bracts 8, membranous, acutely oval; rays golden- 

 yellow, ovate-oblong, 2 cm. long; chaff linear, equaling the disk- 

 flowers; achenes black, flat, 5 mm. long; awns 2, 3 mm. long, or 

 with a third half as long, awns and edges of the achene retrorsely 

 barbed. 



Frequent in shallow streams about San Bernardino, apparently 

 less common toward the coast. August-November. 



2. B. pilosa L. Annual; stems erect, usually branched from 

 the base, 4-6 dm. high, glabrous or sparsely pilose-pubescent; leaves 

 pinnate, pilose-pubescent; leaflets 3-5, irregularly serrate or incised, 

 15-25 mm. long; heads scattered, few, 10-12 mm. broad; rays none; 

 achenes narrow, linear, about 1 cm. long. 



Frequent along streets and irrigating ditches. Native of tropical 

 America. 



35. BEBBIA Greene. 



Much branched suffrutescent plants with few mostly 

 opposite narrow leaves, and scattered discoid heads. 



