998 Compositae. 
narrowed at both ends, shortly petiolate, quite entire near both ends, 
sharply or deeply serrate on other parts of the margin, scabrid above, 
shortly hispid-pubescent below, 1,5—3*/, by 4mm to 1 cm; petioles 
ranging up to 27/, cm. Capitula hemispherical, 5—12 mm long, 
on hispid peduncles of 2"/,—9 cm in a lax open corymbose cyme. 
Outer involucral bracts linear, puberulous, rather falling short of 
the inner which are broader and more pubescent. Achenes oblong, 
5 mm long, slightly hairy upwards, not winged, compressed. Aristae 
filiform, shorter than the achene, inconspicuously ciliate. — Flow. 
March to April. 
N. v. Islands of the Nile near Aswan. 
Also known from Nubia. 
574. (84.) Bidens Linn. 
Capitula heterogamous radiate; ray-flowers ligulate 1-seriate 
female or neuter, occasionally wanting and the capitula thus homo- 
gamous. Involucre sub-2-seriate, inserted around an often dilated 
receptacular disk, outer bracts often herbaceous, inner membranous. 
Scales of receptacle nearly plane or slightly concave. Anther-hase 
entire or minutely sagittate. Style-branches with abrupt appendices. 
Achenes 4-angled or compressed, linear or oblong, often elongate 
and narrowed upwards, crowned with 2—4 retrorsely barbed aristae. 
— Herbs with opposite pinnati- or ternati-sect or undivided leaves 
and solitary or loosely cymose pedunculate yellow or white con- 
spicuous capitula. 
A large genus of warm and temperate regions in both hemispheres. 
1377. Bidens pilosus L. Spec. Plant. I (1753), p. 832. — 
Aschers.-Schweinf. Ill. Flor. d’Hg., p. 89 no. 550. — Sickenberg. 
Contrib. Flor. d’Eg., p. 226. — DC. Prodrom. V, p.597. — Bidens 
leucantha Willd. Spec. Plant. HI, p. 1719. — DC. Prodrom. V, p. 598. 
— Bidens abyssinica Sch. Bip. in Walp. Rep. VI, p. 167. — Bidens 
abortiva Schum. and Thonn. Plant. Guin., p. 381. — An erect annual, 
9—100 cm high, glabrous or somewhat pilose. Stem and branches 
quadrangular. Leaves ovate, mostly pinnately lobed occasionally 
undivided, 2—16 cm long including the petiole, which ranges up 
to 51/, cm membranous; lobes 1—5, opposite with a terminal one, 
ovate or lanceolate, acuminate, shortly stalked, serrate or incisely 
toothed, ranging up to 64/, by 5 em. Capitula hemispherical 5 mm 
to 1 cm diameter in flower, elongating and widening upwards in 
fruit, on peduncles or pedicels of 1—10 em, in a lax open corymbose 
cyme. Involucral bracts linear, glabrous ciliate or pubescent, acute 
or subobtuse, 5—8 mm long, lax and spreading in fruit. Disk- 
