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 arvensis, 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, 



