Diotis.'] XL VI. COMPOSITE t CORYMBIFER^E. 
243 
Subtribe I. Tubiflor2K. Heads discoid.' (Tab. IV. C.) 
(Gen. 24—33.) 
* Pappus of awns or wanting. (Gen. 24 — 27.) 
24. Bidens Linn. Bur-marigold. 
Pappus of 2 — 5 persistent awns, which are rough with minute 
deflexed prickles. Receptacle chaffy. Involucre of many scales ; 
the outer ones or bracteas often leafy. (Heads sometimes with 
aneuter ray.) — Name : bis, double, and dens, a tooth; from the 
awns or teeth which crown the fruit. 
1. B. cernua L. ( nodding B.) ; flowers drooping, bracteas 
lanceolate entire (longer than the involucre), leaves lanceolate 
serrate undivided, bristles of the fruit about 3 erect. E. B. 
t. 1114. 
Sides of rivulets, ditches, and lakes, frequent. 0. 7 — 10. — Stem 
1 — 2 ft. and more high, branched and slightly hispid. Leaves gla- 
brous, deeply serrate. Flowers large, greenish yellow. 
2. B. tripartita L. ( trifid B.) ; leaves tripartite, leaflets lan- 
ceolate deeply serrate, bristles of the fruit 2 — 3. E. B. 
t. 1113. 
Marshy places, sides of ponds and lakes. 0. 7 — 9. — Readily 
distinguished by its divided leaves. The flowers, which are slightly 
drooping, are smaller than those of B. cernua. Both species have 
occasionally a ray of 3-toothed neuter florets. 
25. Diotis Desf. Cotton-weed. (Tab. IV. C.) 
Pappus 0. Cor. with two ears at the base, which border the 
gerrnen and remain upon the fruit. Receptacle chaffy, its scales 
fringed. Involucre imbricated hemispherical. — Named from 
die, two, and our, wroc, an ear ; from the ear-like appendages to 
the fruit. 
1. D. maritima Cass. ( Sea-side C .) Santolina L. : E. B. 
t. 141. 
Sandy sea-shores, principally on the east and south of England. 
Jersey. If. 8, 9. — Root running deep into the sand. Leaves 
numerous, oblong, covered with a white dense tomentum, as are the 
scales of the involucre, which in a great measure conceal the small 
yellow corollas. 
1 In Bidens there is occasionally a true ray ; in Tanacetum somewhat tubular 
florets with a short ligule ; and in Artemisia. Gnauhalium, and Pctasites. slender 
ones with a filiform inconspicuous erect ligule are sometimes observed in the cir- 
cumference, but in these cases the heads can scarcely be said to be rayed. On the 
other hand some species of Senecio, in the second subtribe, are without a ray, and 
some species of Etigeron and Inula have it erect and so inconspicuous that they 
might almost be looked tor in the present snbtribe. 
M 2 
