1016 Tabor .— The Leaf Buds of Archylaea alternifolia. 
runs from the base to the apex of the leaf. The secondary veins at some 
distance from the margin are united by a system of bundles, running 
parallel to the edge of the leaf. From these bundles short branches run 
directly towards the margin, to become joined up in their turn by another 
system of connecting bundles. Finally, short branches from the outer 
marginal series pass out towards the edge of the leaf and end blindly in the 
mesophyll. In the lower part of the leaf the margin is quite entire, but in 
the upper quarter—from the broadest part to the apex—it exhibits a number 
(40-44) of shallow notches. Towards each notch one or more ultimate 
branches of the marginal bundles are directed. No water stomata were 
found in or near the notches. On the other hand, the cells of the mesophyll, 
among which the vascular bundle ends, are closely compacted and filled 
with darkly stained contents. The opacity of the cells makes it practically 
impossible to ascertain the nature of their contents. The presence of tannin 
in other parts of the leaf favours the suggestion that the contents of these 
cells included tannin, which has interacted with traces of iron salts, derived 
from the cans in which the material was preserved. The significance of 
these notches in the mature leaf will be apparent when the structure of the 
young leaves is described. 
The upper epidermis is devoid of stomata, but these are numerous on 
the lower side of the leaf. They are of the Rubiaceous type—that is, they 
show from two to five subsidiary cells arranged parallel to the guard cells 
(PI. LXXIX, Fig. 2). 
The mesophyll is bifacial, with one, sometimes two, layers of palisade 
tissue of ordinary type. No sclerotic cells, such as occur in Thea, Camellia , 
and other members of the order, are found in the mesophyll of Archytaea. 
The upper epidermis in the young leaf is one-layered, but early divides into 
two layers, the lower and larger cells forming a conspicuous hypoderm in 
the mature leaf. The inner walls of the hypoderm cells are strongly 
gelatinized, the swollen stratified wall encroaching on and occupying the 
greater part of the lumen of the cell (PI. LXIX, Fig. 3). Rarely these 
hypoderm cells undergo a second division. The epidermal cells, on the other 
hand, invariably become further divided by vertical walls into a group of four 
to eight cells. The cells of the lower epidermis are not divided, but, with the 
exception of those connected with the stomata—the guard cells and subsidiary 
cells—they undergo gelatinization of the inner walls. 
Cells with mucilaginous walls also occur scattered throughout the lower 
part of the mesophyll, and are abundant in the outer cortex of the stem. 
The young leaves. The buds examined were composed of four or five 
leaves. The outermost leaf, which is generally three-quarters grown, has in 
all essentials the structure of the mature leaf; its basal part is tightly rolled 
around the inner leaves of the bud. The next younger leaf is clearly 
visible (PI. LXXIX, Fig. 1), its apex often extending well above the tubular 
