350 FOUNDATIONS OF BOTANY 
of the bugloss (Fig. 247, 6); sometimes they are decidedly 
barbed. If the barbs are well developed they may cause 
the hairs to travel far into the flesh of animals and cause 
intense pain. In the nettle (Fig. 247, a) the hairs are 
efficient stings, with a brittle tip, which on breaking off 
7 ad . 
\. Fie. 245.— Euphorbia splendens. 
The spines are dead and dry 
stipules. 
Se | 
jin exposes a sharp, jagged 
Y. tube full of irritating 
fluid. These tubular hairs, 
with their poisonous contents, NN 
will be found sticking in the me. 246, — Thorn 
skin of the hand or the face “*P™** of Hocust. 
after incautious contact with nettles, and the violent itching 
which follows is only too familiar to most people. 
419. Cutting Leaves.— Some frasses and sedges are 
generally avoided by cattle because of the sharp-cutting 
edges of their leaves, which will readily slit the skin of 
one’s hand if they are drawn rapidly through the fingers. 
Under the microscope the margins of such leaves are seen 
to be regularly and thickly set with sharp teeth like those 
of a saw (Fig. 247, ¢, d). | 
