stipules, as well as the persistent pedestal of the leaf to which they are attached, are densely lined on the inner face with pale brown hairs like a thick fur, while they are glabrous and dull olive-green externally.

In Guaiacum officinale (figs. 131, 132) the stipules are axillary and connate into

connate, and form a sheath, which encloses the younger parts of the bud.

In Alstonia scholaris, belonging to the Apocynaceœ, the leaves (fig. 134) are whorled at the apex of each shoot in groups of six to nine, narrowly oblongelliptic, narrowed to both ends, but obtusely pointed.

The short petioles are semi-terete, flattened above, and furnished with a ligule or outgrowth from the base of the upper face, protecting the bud. This ligule is

triangular, obtuse, pale green, 1.5-2 mm. long; collectively they form a whorl, covering all but the extreme apex of the bud. (See also 14.)

In Spergularia rubra (fig. 135) the leaves are opposite, long, narrow, fleshy, and somewhat flattened above. The

FIG. 131.-Terminal shoot, nat. size; n, node; st', connate stipules; st", connate stipules covering the terminal bud.

FIG. 132.-Terminal shoot with lamina of leaves removed, x 2; st' st", stipules as in fig. 131; b, lateral bud.

stipules' are scarious, inserted at the node just beneath the leaves, so that they pass round the back of the latter, completely enclosing them in bud, and covering their bases even when fully developed. This is a most unusual arrangement. The stipules are also 1 See Dickson, Journ. Bot. 1878, p. 316.

connate at the base, with an interpetiolar, free, ovate, acute piece, which is sometimes entire, sometimes divided at the apex into two or three setaceous teeth, as if these free portions consisted of one stipule from each

FIG. 133.--END OF SHOOT OF GARDENIA FLORIDA. Nat. size. L', L', a pair of leaves with their connate stipules, St', showing the fissured side only; L", L", the youngest unexpanded pair of leaves, with their stipules (St") completely investing the terminal bud.

leaf united. These stipules are very advanced in bud, and evidently attain full size long before the expansion of the leaves, many pairs of which they completely cover and protect. They are persistent, covering the bases of the leaves when full grown. They thus pro

tect the terminal and axillary buds, the latter being

very freely produced.

The stipules in this case may be compared to the

S

FIG. 134.-ALSTONIA SCHOLARIS. Terminal whorl of leaves to show ligules covering the bud. Reduced about one-half.

FIG. 135.-SPERGULARIA
RUBRA, x 3.

S, stipule; L, leaf.

ocreas or sheathing and scarious stipules of the Polygonaceae. The stipules of the latter are, however,

continuous with the edges of the petiole, which appears as a strong midrib to the sheath; while those of Spergularia are perfectly free from the leaves.

PROTECTION BY HAIRS

In other cases buds are protected by hairs. These fall into three main categories:

1. Hairs which form a felt or fur.

2. Stiff, bristly hairs.

3. Glands.

Many species are glabrous, or hairy, according to the conditions in which they live; for instance, there is a common English Polygonum which, from growing sometimes on land and sometimes in water, is known as P. amphibium. Land specimens are hairy, especially at the nodes, while specimens growing in water have no hairs.

It has been suggested that the hairs at the nodes prevent small climbing insects, such as ants, from reaching the flower, which they would rob of its honey without rendering any service in return in the way of cross-pollination. When growing in water the plant obviously needs no such protection.

as,

Protection by Fur or Felt

Hairs forming a fur or felt may act in various ways; for instance:

1. By warding off excessive moisture.

2. By preventing too much transpiration.

3. By protecting the buds from excessive cold.