MR. PERCY GROOM ON BUD-PROTECTION IN DICOTYLEDONS, 259 
of staining of the protoplasm decrease as the cells approach the non-secretory epidermal 
cells. The subsequent changes consist in the radial division and elongation of the external 
(epidermal) cells to form a secretory layer, and the division and elongation of the 
internal cells to form the conducting parenchyma (fig. 4). As the secretory cells grow 
older their staining qualities diminish, and the nucleus finally becomes a feebly-staining 
bubble-like body. "Thus it is seen that the villus is an emergence. ‘The villi are red in 
colour and secrete mucilage and resin. 
Coprosma Baueriana (and C. Baueriana var. variegata) is a native of New Zealand. 
Its leaves are opposite, stalked; their bases are continuous with small triangular inter- 
petiolar stipules. But the stipules are really sheathing in that they are continued asa- 
small cushion on the inner face of the leaf-base. The villi form a complete zone round 
the stem, being perched on the top of these peculiar sheathing-stipules. Each triangular 
stipule possesses about five villi, the median one of which is the largest and is situated 
at the apex of the triangle (fig. 6). 
The growing-point is at the bottom of a small pit formed just as in Cosmibuena. 
Development of the Stipules.—The development of the leaves and their stipules is 
so nearly simultaneous that I only succeeded in discovering leaves without well-defined 
stipules in a few lateral buds. Тһе young lateral bud is flattened in contour; the first 
leaves arise as distinct swellings in the transverse plane of the bud. Very shortly after 
the tissue between these two leaves grows up, so that at this stage there is an annular 
outgrowth with two considerable prominences, which are the two leaves. But the 
interpetiolar part soon grows more vigorously at its median point, so as to form the 
large median terminal villus (fig. 6). Тһе other villi arise successively lower down, 
those lying in an axillary position forming later. 
Structure and Development of the Villi.—Each villus is a pear-shaped, shortly-stalked 
body, possessing the typical palisade-like secreting layer and a central mass of con- 
ducting parenchyma-cells. Amongst the latter are many large cells containing raphides. 
The villus develops like that of Cosmibuena (figs. 7 and8). The modified nuclei of the 
old cells are especially noticeable. | 
Hoffmannia macrophylla (syn. Higginsia macrophylla) is а native of Guatemala. 
Between each pair of large opposite leaves lie two small triangular hairy stipules. Тһе 
whole of the upper (inner) face of each stipule is raised into irregular glandular ridges 
and lobes. Each glandular elevation consists of a superficial layer of palisade-like 
secretory cells covering a tissue of somewhat elongated parenchyma-cells (figs. 9 and 10). 
Many of these parenchyma-cells are enlarged and contain raphides. Аз in all Rubiacee, 
the stipules and young parts generally are rich in tannin, which is especially collected in | 
the epidermis hairs and subepidermis of the stipule. Resin and gummy mucilage form 
the secretion. Тһе glandular outgrowths and some (all?) of the stipular hairs secrete. 
In the latter one easily sees pits in the transverse walls of the cells (fig. 11) and pro- 
toplasmic intercommunication. The cuticle of these hairs is raised, but outside 
the unbroken cuticle of many of the hairs one sees the small masses of the secretion, 
which, however, may possibly have been secreted by other cells. | 
The growing-point of the stem is surrounded by several concentric sheaths belonging 
