COMPOSITAE COMPOSITE FAMILY 
PRICKLY LERGUCGE). (MEEK THISTLE 
Lactuca Scariola L. 
The Prickly Lettuce seems to have been introduced into this 
country from Europe about 1863 and is now common nearly 
throughout. In some places the young leaves are collected in 
great quantities in spring and used 
as a salad vegetable. Sheep eat the 
young leaves quite greedily and 
cattle seem to like them also. Gen- 
erally, however, it is considered a 
noxious weed because its hard stems 
dull reaping knives and its copious 
juice is a major annoyance in thresh- 
ing machinery. 
The stem is stiff, leafy and branch- 
ed near the top. It grows 2-7 feet 
high and is smooth, except that the 
lower portion is somewhat prickly. 
The alternate leaves are spiny 
toothed, sessile and clasping, and 
usually there is a row of prickles 
along the whitish green midrib below. 
The heads are very numerous 
with 6-12 pale yellow flowers, bloom- 
ing from July to September, in each. 
The involucre is cylindrical and the 
outer bracts are only about a third 
as long as the inner. The brown 
akene has a threadlike beak of 
equal length, and a white pappus of 
silky hair. 
The Wild Lettuce or Horseweed, Lactuca canadensis L., grows 
3-10 feet high and is smooth throughout. The leaves are quite 
variable. Those of the main stem are usually somewhat pinnately 
lobed, sessile or clasping, and 2-8 inches long. The upper ones are 
usually smaller and entire, and sometimes all are nearly white. 
Each of the numerous heads contains 12-20 pale yellow flowers. 
The akenes are oval, flat and about as long as the slender beak. The 
pappus is white. Moist open places are favored by this plant, from 
Nova Scotia to British Columbia and south to Georgia, Alabama, 
Arkansas and Colorado. 
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