COMPOSITAE (COMPOSITE FAMILY) 489 
tary, terminal, about an inch broad; rays fifteen to twenty, 
neutral, white, three-toothed, spreading, becoming reflexed as 
they wither; disks yellow, hemispheric, growing cone-like with 
age, the florets tubular and perfect ; bracts of the involucre oblong, 
scarious margined, obtuse, usually somewhat hairy. Achenes 
oblong, ten-ribbed, roughened with glandular tubercles, and 
without pappus; they are nearly always found as an impurity 
in seeds of grass and clover. (Fig. 340.) 
Means of control 
The plant is an annual, and, if it were persistently destroyed 
before any seed had dropped into the soil to vex another year’s 
crop, it must needs disappear. It would pay even to hand-pull it, ~ ~~ 
but prompt cutting would be sufficient. In grain fields the crop 
may be relieved of much of the crowding growth of the weed by 
harrowing out the seedlings in the spring. 
FIELD OR CORN CHAMOMILE 
Anthemis arvénsis, L. 
Introduced. Annual or biennial. Propagates by seeds. 
Time of bloom: May to August. 
Seed-time: June to September. 
Range: Nova Scotia to Virginia, and westward to Michigan and 
Missouri; also on the Pacific Coast. 
Habitat: Cultivated fields, meadows, roadsides, and waste places. 
Somewhat like the Mayweed, but without its unpleasant odor 
and acrid juices. It is low, seldom exceeding a foot in height, 
some of its many branches decumbent, others ascending, very 
leafy, and finely hairy. Leaves sessile, one to three inches long, 
pinnate, once or twice divided, much less feathery than the May- 
weed. Heads numerous, usually exceeding an inch in width, with 
ten to twenty white, spreading, two-toothed rays, pistillate and 
fertile; disk-florets perfect; bracts of the involucre are oblong, 
obtuse, hairy, with scarious margins. Achenes oblong, obscurely 
four-angled, crowned only with a minute border for a pappus. In 
some localities this is a worse weed than its ill-scented relative, 
