on: Fig. 106. Section of the same.]

113. =The Bulb=, strictly so-called, is a stem like a reduced corm as to
its solid part (or plate); while the main body consists of thickened
scales, which are leaves or leaf-bases. These are like bud-scales; so
that in fact a bulb is a bud with fleshy scales on an exceedingly short
stem. Compare a White Lily bulb (Fig. 107) with the strong scaly buds of
the Hickory and Horse-chestnut (Fig. 72 and 73), and the resemblance
will appear. In corms, as in tubers and rootstocks, the store of food
for future growth is deposited in the stem; while in the bulb, the
greater part is deposited in the bases of the leaves, changing them into
thick scales, which closely overlap or enclose one another.

114. =A Scaly Bulb= (like that of the Lily, Fig. 107, 108) is one in
which the scales are thick but comparatively narrow.

[Illustration: Fig. 107. Bulb of a wild Lily. 108. The same divided
lengthwise, showing two forming buds of the next generation.]

[Illustration: Fig. 109. A ground leaf of White Lily, its base (cut
across) thickened into a bulb-scale. This plainly shows that bulb-scales
are leaves.]

115. =A Tunicated or Coated Bulb= is one in which the scales enwrap each
other, forming concentric coats or layers, as in Hyacinth and Onion.

116. =Bulblets= are very small bulbs growing out of larger ones; or
small bulbs produced above ground on some plants, as in the axils of the
leaves of the bulbiferous Lilies of the gardens (Fig. 110), and often in
the flower-clusters of the Leek and Onion. They are plainly buds with
thickened scales. They never grow into branches, but detach themselves
when full grown, fall to the ground, and take root there to form new
plants.

[Illustration: Fig. 110. Bulblets in the axils of leaves of a Tiger
Lily.]

117. =Consolidated Vegetation.= An ordinary herb, shrub, or tree is
evidently constructed on the plan developing an extensive surface. In
fleshy rootstocks, tubers, corms, and bulbs, the more enduring portion
of the plant is concentrated, and reduced for the time of struggle (as
against drought, heat, or cold) to a small amount of exposed surface,
and this mostly sheltered in the soil. There are many similar
consolidated forms which are not subterranean. Thus plants like the
Houseleek (Fig. 91) imitate a bulb. Among Cactuses the columnar species
of Cereus (Fig. 111, _b_), may be likened to rootstocks. A green rind
serves the purpose of foliage; but th