184 : WEEDS AND USEFUL PLANTS. 
It is, however, quite an objectionable weed, on account of the vast quan- 
tity of its adhesive fruit, in autumn. There appear to be several varie- 
ties of the plant,—noticed in Torrey & Gray’s N. A. Flora. 
** Akenes slender, linear, 4-sided, beaked at summit, mostly smooth. 
Se ; yi cate terminal and 
axillary peduncles ; outer scales of the involucre scarcely as long as the 
inner ones ; akenes long and slender, 4-angled and grooved, 3 — 4-awned. 
BirtnnatE Bivens. Spanish Needles. es 
Plant glabrous. Root annual. Stem 2-4 feet high, quadrangular, brabched. Leaves 
2-4 or 5 inches long, deltoid-ovate in the ine ; petioles 1-3 or 4 inches long. | Heads 
oblong, slender ; rays 3-4, obovate, small, yellow with dark veins ; disk-flords about 20, 
H # 
_ _ Fig. 125. Spanish Needles (Bidens bipinnata.) 126. A miture akene, with 4 downwar 
- bristly awns. (Bidens bipinnata.) 126, A mature akene, with 4 dov 
