126 ELEMENTS 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 
Fig. 92. Stinging Hairs and Cutting Leaves. (All much magnified.) 
a, stinging hairs on leaf of nettle; 0, 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. 
