126 ESSENTIALS OF BOTANY 
Buckeye, horse-chestnut, and buckthorn leaves are so 
bitter that browsing animals and most insects let them 
alone. Tansy, ragweed, boneset, southernwood, and worm- 
wood are safe for the same reason. The nauseous taste of 
erat 
LIZZ TEDPDZEDTEEEZ 
Fic. 92. Stinging Hairs and Cutting Leaves. (All much magnified.) 
a, stinging hairs on leaf of nettle; b, bristle of the bugloss; c, barbed margin 
of a leaf of sedge; d, barbed margin of a leaf of grass. 
many kinds of leaves and stems, such as those of the potato, 
and the fiery taste of horse-radish, make these substances 
uneatable for most animals. 
Poisonous plants are usually shunned by grown-up 
animals, though the young ones will sometimes eat such 
plants and may be killed by them. 
