COMPOSITAE (COMPOSITE FAMILY) 475 
Stem one to three feet high, stout, erect, smooth, pale green, with 
short, stout branches. Leaves light green, lance-shaped, regularly 
toothed, pointed at both ends, with winged petioles or the upper 
ones sessile. Heads large, on short, stout peduncles, the outer 
bracts of the involucre six to eight, lance-shaped, large, and leaf- 
like, often toothed, erect, their height sometimes two to five times 
exceeding the disk; rays wanting; disk-florets funnel-shaped, 
four-lobed, pale yellow. Achenes brown or olive, nearly a half- 
inch in length, flat, smooth or nearly so, three-awned, the outer ones 
nearly three-fourths as long as the achene, the central one usually 
shorter, and all barbed downward. 
Control of the weed depends on allowing none of the plants to 
mature their fruits. 
SWAMP BEGGAR-TICKS 
Bidens conndta, Muhl. 
Other English names: Purple-stemmed Stickseed, Harvest Lice. 
Native. Annual. Propagates by seeds. 
Time of bloom: August to October. 
Seed-ttme: September to November. 
Range: New England to Minnesota, southward to the Carolinas 
and Missouri. 
Habitat: Wet meadows and fields, banks of streams, and ditches. 
This native American has established itself in Europe, where it 
is very cordially disliked. Stem one to six feet or more tall, erect, 
smooth, purple, branching freely. Leaves deep green, usually 
undivided or some of the lower ones three-cleft, narrowly lance- 
shaped, coarsely toothed, with long, slender petioles. Heads 
about a half-inch broad, numerous, on short, slender peduncles, 
the outer bracts of the involucre few, obtuse, entire, extending not 
far above the head; rays usually wanting, but, when present, golden 
yellow; disk florets orange-yellow, five-lobed. Achenes dark 
brown, rather thick, wedge-shaped, tubercled, four-angled, four- 
awned, or the outer row flattened on one side and three-awned, 
the sides of achene and awns downwardly barbed. 
Means of control 
Drainage and cultivation of the ground; prevention of seeding 
by frequent, close cutting: 
