612 DR. M. T. MASTERS ON THE PASSIFLORACEZÆ. 
Stem.—In Passiflora quadrangularis and also in Barteria nigritiana, sections of the 
stem show the following tissues :—On the exterior is an epidermis of squarish cells desti- 
tute of chlorophyll, and thickened on the outer wall. Within the epidermis is a quan- 
tity of small-celled parenchyma filled with chlorophyll. The constituent cells of this 
cellular envelope vary in size according to the age of the stem. The liber-bundles con- 
sist of large fusiform, thick-walled, pitted wood-cells, arranged in masses which, when 
seen in section, have a kidney-shaped outline, the concavity being directed inwards 
towards the centre of the stem. “Within these liber-bundles is more parenchyma invest- 
ing the wood, which consists of ordinary wood-cells closely packed, and surrounding large 
pitted ducts and, towards the centre of the stem, spiral vessels. The middle of the 
branch is occupied with an abundance of pith, whose cells contain, at some seasons, 
starch-grains, and at all times conglomerate raphides. (See Plate LXV. fig. 6.) 
Tendrils.—These are in structure similar to the branches, consisting of an epidermis 
surrounding a celular envelope, in which are imbedded liber-cells arranged as in the 
branches. Within these is parenchyma with conglomerate raphides, and surrounding 
wood-cells, in which there are but few vessels. In the centre is the pith. 
Leaf.—The structure of the leaf in Passion-flowers presents, so far as I have seen, no 
features of special interest; and hence the subject may be passed over with a brief refer- 
ence to the epidermis and to the arrangement of the vascular bundles. The epidermis 
consists of flat cells with sinuous outline, between which are a great number of small 
oval stomata, bordered on each side by a semilunar guard-cell. 
In some of those species, the lower surface of whose leaves is studded over with ocel- 
late glands, the structure is as follows :—The ordinary epidermal cells are, in the species 
examined, less sinuous in their outline, and arranged concentrically around the circular 
gland. This latter is composed of a large number of very small hexagonal cells densely 
packed together, each cell being two or three times less in magnitude than the adjacent 
epidermal cells (Plate LXV. fig. 7). 
Petiole.—In transverse section the petiole of Passiflora quadrangularis is boat-shaped. 
In structure it consists of the usual epidermis surrounding parenchyma in which are 
plunged eight large vascular bundles, and sometimes others of smaller size interposed. 
The usual arrangement is as follows :—Six large bundles disposed in a ring around the 
central parenchyma, the largest bundle being uppermost. Each of the bundles has in 
transverse section a deltoidal outline, the apex of the triangle being directed inwards 
towards the centre, while the broad base, consisting of cellular tissue and cambium- 
cells, is directed towards the circumference. The remaining bundles oceupy each one of 
the upper corners of the leaf-stalk, and have their cambium-cells also directed towards 
the periphery, so that these wedge-like (in section) masses of woody tissue form a broken 
circle as in a branch, but are more interrupted (Plate LXV. fig. 8). 
Midrib.—A transverse section of the midrib, in the centre of its course, shows a similar 
structure to that just deseribed, but with only four woody bundles, placed one on either 
side, one at the top, and one at the bottom. The eambium-cells are external as in the 
petiole (Plate LXV. fig. 9). | 
Petiolar Lar —In neut alata these glands are EEE the concavity being 
