‘ - a f= } ¢ 
fs a> TY 4 4 
SS Ae eg Pe hy 
re Ne EW epee Be 7.8 PR eh er he . Tr ae ben OF pt 7 ‘ oe er ' € ? t - , M ertd.s ow a 
my | tae ey xb Str c . ai ye ie ay Rane, G / j ] / ey 4 ? / re . i Pa $ 
wo] 4 Nh Teenie” } by e® , PD 2 ys ~ > OPP +. 7 
i { y ‘ - , ~ APT fe 
out of Cells. 63 
y 
The Construction of the Plant 
“result from the walls of hairs becoming thicker and woody, ; 
7.¢. by the deposition of ignine. Hairs are not often found 
in the interior of plants, but occur in the air-passages of 
Nympheeaceze. Séznging-hairs are such as secrete an acid 
corroding fluid which escapes when they are injured; they = 
often stand, as in the stinging-nettle, on a cushion-like 
base (Fig. 88). Prickles (Fig. 90) consist of a great number 
of thick-walled woody cells. Scales [or peltate hairs| exbibit + 
Fic. 91.—Peltate hair from the leaf of ZZ- Fic. 92.—Glandular hair from the leaf-stalk  _ * 
agnus, seen from above. (x 125.) of Lamium purpureum.(X 370.) 
a great complication of structure, consisting of an elongated 
epidermal cell, the pedicel-cell, which bears at its apex a 
number of cells expanded into the form of a shield (Fig. 91). 
Glands consist of anumber of cells puffed out like bladders, 
in which a viscid and often resinous fluid is secreted. Thus, 
for example, the leaf-buds are often rendered viscid by a . 
gummy substance, or one composed of a mixture of muci- 
lage and drops of balsam, the first resulting generally from Y 
the conversion into mucilage of an epidermal layer lying 
beneath the cuticle, as in the violet, horse-chestnut, and — tos 
plum. (See Fig. 80, p. 54.) If glands are elongated into | 
