COMPOSITAE (COMPOSITE FAMILY) 541 
Stem erect, with short lateral branches, round, smooth except 
for a few prickles near the base, sometimes attaining a height of 
seven feet but usually two to five feet tall; occasionally it has a 
purplish tinge. Leaves alternate, light green, oblong, variable,-often 
obtuse at tips but sometimes acute, with wavy, prickly-toothed 
Fie. 3874. — Prickly Lettuce Fic. 875. — True Prickly 
(Lactuca scariola, var. integrata). Lettuce (Lactuca scariola). 
x4. xt. 
edges and thick, whitish green midrib, closely set with spines on 
the under side, sessile, clasping, auricled at base. Leaves of plants 
growing in the open have a vertical twist at the base which causes 
their edges to point north and south; plants growing in the shade 
have not this twist to the leaves. Heads numerous, in a large 
