Sunflower Tribe 417 



ous spreading bracts, the inner of broad membranous 

 erect ones. Rays broad, pistillate and often fertile, 

 sometimes neutral. Chaff of receptacle linear, thin, 

 scarious, deciduous with the fruit. Achenes flat or 

 somewhat concavo-convex, margined. Pappus a minute 

 callous cup or a pair of palese. 



1. It. DouglasiiDC. 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. Ii. 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. 



33. 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 united at base, the 

 outer often foliaceous 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. speciosa Parish. 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, 



