MR. PERCY GROOM ON BUD-PROTECTION IN DICOTYLEDONS. 261 
Food is conducted to the secretory cells partially in the form of carbohydrates, for 
transitory starch occurs in the conducting parenchyma of the colleter. | 
Gardenia laurifolia (2) resembles the preceding, except that the leaves are in whorls 
of threes, and when young are densely coated with hairs (fig. 14). 
In Pavetta indica the long strap-like colleters and the exceedingly elongated, often 
spirally thickened, woolly hairs form the basis of a eomplete and striking protective 
mechanism. | 
In the evil-smelling Pederia fætida the colleters are unusually large, and their 
relatively late development suggests a more lasting function than is usual to colleters. 
In Sarcocephalus sp. the villi are numerous; the simple hairs are represented by a 
papillose epidermis on the outer (lower) faces of the young leaves. 
АРОСУМАСЕХ. | 
Tabernemontana dichotoma.—Treub describes the bud аз protected by a coating of а 
wax-like substance secreted by colleters; but it merits a more close examination. "The 
leaves are decussate, stalked, but connate. Many growing buds present the following 
appearance :—The shoot ends in two leaves, the fused < bases” of which cover the 
younger leaves and apex, and only leave a narrow slit between them. This terminal 
slit (fig. 19) and the parts adjoining are covered by secretion. Forcing these two 
terminal leaves apart, one sees that not only are the “bases” of the leaves fused, but 
that there are minute ledge-like outgrowths growing out from the inner faces of the 
two leaf-“ bases." These ledge-like outgrowths, together with the fused leaf-bases, 
enclose a bell-shaped cavity, in which lie the younger leaves (fig. 22). The only opening 
to this cavity is the above-mentioned slit which runs in a plane at right angles to the 
two leaves in question. The walls of the cavity, or chamber, are lined by villous 
colleters which secrete copiously. From the floor of the chamber rise two more leaves 
arranged in a plane at right angles to the preceding; they are merely a repetition in 
miniature of the older pair, except that their p i / 
interbasal chamber encloses the growing | Yi 
point and tiny leaf-rudiments. When growth f t / a 
takes place the largest enclosed 1еауез push 
/ Wy 
Y <) --% 
SSS 
BA 
through the slit, which, it will be noticed, has 
_ its plane coinciding with that of the emerging 
leaves (figs. 20 & 21). Тһе lips of the slit are 
thus forced asunder, or naturally gape asunder 
by their own growth, and the young leaves 
emerge, doubtless, coated with the secretion. 
Lower down the stem the fused “bases” с. 
of the mature leaves form a tight-fitting collar Diagrammatic longitudinal section through bud of 
t th Tabernemontana.—ch, chamber; s, slit; 1, ledge 
round the stem, and serve to protee е (stipule); с, colleters; lb, base of leaf; st, stem 1 
axillary bidas- - yl, younger leaf enclosed in chamber. 
Structure of the Villi.—The villi call for no special description ; they are perfectly 
normal in structure, but spherocrystals occur in place of raphides. Delicate vascular 
