Blepharipappus. C01IP0SITJE. 357 



53. BIDENS, Linn. Bur-Marigold. 



Head inany-flowered, heterogamous and the 3 to 10 rays neutral, or homogamous 

 and tlie flowers all perfect and tubular. Involucre double ; the outer of a few mostly 

 foliaceous loose or spreading scales ; tlie inner of several erect and more membrana- 

 ceous scales. Receptacle flat or convex ; the thin narrow chaff deciduous with the 

 fruit. Akenes obcompressed, either broad and very fiat or narrow, beakless, bearing 

 a pappus of 2 to 4 rigid and retrorsely barbed awns. — Annual or perennial herbs ; 

 with opposite leaves, and small or middle-sized heads of yellow or sometimes white 

 flowers ; some of them vile weeds. The species are numerous, and very widely 

 distributed over the world, but there are remarkably few in California or in the 

 Pacific region. 



* Akenes broad : leaves merely serrate. 



1. B. chrysanthemoid.es, Michx. Annual, glabrous, leafy to the top, a foot or 

 two high : leaves broadly lanceolate, tapering to both ends, closely sessile, serrate, 

 3" to 5 inches long : heads rather large and showy : scales of inner involucre broad : 

 rays 8 to 10, gulden yellow, oblong or oval, an inch long: akenes wedge-shaped ; 

 their margins and the 2 to 4 rather long awns barbed with rigid or almost prickly 

 reflexed bristles. 



Wet places, apparently not rare through the western part of the State. Extends to Mexico, 

 anil is common in all the Atlantic States. 



B. CERNUA, Linn., a tall variety of which grows in Oregon, has smaller leaves, heads without 

 rays, or with short ones of lighter yellow, and smaller barbs to the akene and awns. The two per- 

 haps run together. The plant named/.', cernita by Hooker and Arnott, in the Botany of Beeehey's 

 Voyage, is probably the preceding. 



* * Akenes long and narrow (Spanish Needles): leaves divided or compound. 



2. B. pilosa, Linn. Annual, more or less hairy, or merely the leaves sparsely 

 pubescent : these 3-parted or the lower 5-parted into ovate incisely cleft or sharply 

 -en, Me thin Leaflets: heads small, without rays or with 2 or 3 small ami whitish 

 ones: akenes linear, smooth, or the miter ones upwardly hispid-scabrous, at least 

 towards the summit, 2 — 4-awned. — B. Californicd, 1>C. Prodr. v. 599. Torr. & 

 Cray, FL ii. 354. 



Santa Barbara to Los Angeles, near water-courses, &c. A weed, widely diffused over the 

 warmer coasts, especially of the Pacific : if correctly indentified with /;. r ' . doubtless intro- 

 duced with cattle into California. 



Heterospermttm Xanti, Cray, of I.ow.t California, resembles a Bidens with finely divided 

 leaves, and is intermediate between the two genera. 



54. BLEPHARIPAPPUS, Book., Torr. & Gray. 

 Head heterogamous, with 3 to G pistillate rays : disk-flowers 7 to 12 perfect, some 

 of the central infertile. Scales of the involucre 6 to 10, nearly in a single series, 

 lanceolate, erect, almost equal. Receptacle convex, chaffy; the chaff thin and 

 membranaceous, deciduous with the fruit, Rays short ami broad, cuneiform, .""•- 

 lulled. Style in the ilisk-llnwers long, thickened upwards and hairy. 2-clefl only at 

 the apes (the branches obtuse and tint appemlagcd), or in the centra] ami sterile 

 Bowers nearly entire. Akenes turbinate, silky-villous. Pappus of 10 or 12 linear 

 hyaline seal,,, traversed by a stoul awn-like midrib, the margins lae. i it< l\ Cringed 

 so .i- tu appear plumose, rarelj wanting. Annual, corymbosely or pauiculately 

 branched; l»'th rays and disk-corollas white; the anthers brown-purple. Only 

 one variabli ap< 



