COMPOSITAE (COMPOSITE FAMILY) 543 
In rich, moist soil this weed sometimes 
attains a height of ten feet, but is more 
often three to six feet tall. Stem slender, 
smooth, often glaucous, sometimes of a 
purplish tinge but most commonly deep 
green. Lower and basal leaves lance- 
shaped in outline but deeply and irregu- 
larly lobed, the terminal segment large 
and acutely pointed, the lateral ones un- 
equal in number and size, not opposite, 
and frequently with points turned back- 
ward, narrowing to margined petioles; 
upper leaves much smaller, often entire 
and sessilé. Heads numerous, in a loosely 
branching terminal panicle and in short 
axillary clusters; heads yellow, hardly 
more than a quarter-inch broad, the in- 
volucre cylindric, its inner row of bracts 
linear, the outer ones short and spreading. 
Achenes oblong-oval, tipped with a slen- 
der beak; pappus white, very fine and 
silky. The plant has a strong, unpleasant 
odor resembling opium, and, though cattle 
and sheep eat it readily, it will damage 
dairy products if milch cows get much of 
it. (Fig. 376.) 
Fie. 376.— Wild Let- 
tuce (Lactuca canadensis). 
Means of control the same as for x3, 
Prickly Lettuce. 
ARROW-LEAVED WILD LETTUCE 
4 
Lactica sagittifolia, Ellis 
Other English names: Devil’s Ironweed, Horseweed. 
Native. Biennial. Propagates by seeds. 
Time of bloom: July to September. 
Seed-time: August to November. 
Range: New Brunswick and Ontario to ‘Georgia, westward to the 
Rocky Mountains. 
Habitat: Dry, open soil; fields, meadows, waste places. 
