542 COMPOSITAE (COMPOSITE FAMILY) 
panicle at the summit of the stalk and on short axillary branches ; 
pale yellow, each less than a half-inch broad, on very short 
pedicels; beginning at the top, they open a few at a time, daily. 
Achenes brown, ridged lengthwise, with thread-like beak and 
pappus of fine, white, silken hair. (Fig. 374.) 
Not quite so obnoxious nor so common as the variety just de- 
scribed, but still a very bad weed, is the True Prickly Lettuce (L. 
scariola, L.) differing chiefly in that its prickly ribbed leaves are 
lobed or pinnatifid, and the smooth or sparsely prickled woody 
stalk usually taller; the heads are similar but slightly smaller, very 
numerous. The plant ranges from New England and Pennsylvania 
westward to Michigan and Missouri. (Fig. 375.) 
Means of control 
Deep cutting of the tufted root-leaves, well below the crown, 
with hoe or spud; cutting of flowering stalks at the beginning of 
bloom or earlier. In a grain field, hand-pulling of the young 
flower-stalks before bloom will be a paying operation, as the crop 
will not be worth much if the weed is allowed to absorb the fertility 
and moisture of the soil. Rankly infested ground should be put 
under cultivation for the purpose of stirring dormant seed into life 
and destroying the seedlings. Sheep and young cattle graze the 
young plants freely and prove good assistants in keeping the weed 
in check, but milch cows must not have much of it as the juices 
are bitter and will taint the milk. Seeds are widely wind-sown, and 
it is to the interest of the entire community to see that none are 
allowed to mature in roadsides and waste places. 
WILD LETTUCE 
Lactica canadénsis, L. 
Other English names: Wild Opium, Horseweed, Trumpet Milkweed. 
Native. Annual and winter annual. Propagates by seeds. 
Time of bloom: June to October. 
Seed-time: July to November. 
Range: Nova Scotia _to the Northwest Territory, southward to 
Georgia, Alabama, Louisiana, and Arkansas. 
Habitat: Fields, meadows, roadsides, and waste places. 
