266 МВ. В. 8. ADAMSON ON THE COMPARATIVE ANATOMY 
Group Е. 
The species in this group have petiolate leaves with toothed margins; the 
bundles end in hydathodes, which oceur both at the tip of the leaf and also 
at the tip of each tooth. 
V. Hulkeana, F. Muell. *. 
The petiole is long; the lamina thick and glabrous. tomata are confined 
to the lower side of the leaf. The mesophyll shows the normal differentiation. 
Next the upper epidermis is a layer of clear vacuolated cells, forming a hypo- 
dermal water-tissue f ; also along the lower epidermis are 2-3 somewhat 
irregular layers of cells, distinguished from the spongy tissue by their having 
clear contents and no chloroplasts. This lower water-tissue is much more 
marked in herbarium material of native plants than in cultivated leaves. 
The central and main lateral bundles are transcurrent. The petiole consists 
of cylindrie parenchymatous cells, with the horseshoe-shaped bundle and its 
two main branches ; further branches occur near the top. 
V. Lavaudiana, Cheesem. f. 
The leaves are smaller and hairy, being covered with long- and a few 
short-stalked glandular hairs on both sides ; this character is less marked in 
herbarium material of native plants. Stomata occur on both sides and no 
water-tissue 18 developed. 
V. Fairfeldi, T. Kirk $. 
This is supposed to be a hybrid between the two preceding species, and 
has never been found in the wild state ||. Externally it is very like 
V. Hulkeana, of which Cheeseman regards it as a variety. Short-stalked 
gland-hairs occur in small numbers on the upper side. 
Stomata are found 
on both sides of the leaf. No water-tissue is present. 
The next three species differ in their prostrate mode of growth from the 
preceding and are externally very like one another, differing, as far as 
the leaves are concerned, mainly in size. In all the bundles are embedded. 
V. catarracte, Forst. 
In external characters this is a very variable species. 
The leaves are stiff 
and glabrous, with short petioles. 
Stomata are few in number on the 
upper as well as ou the lower side. The mesophyll, both in cultivated and 
* Bot. Mag. t. 5484, T Huchedé (1907). { Bot. Mag. t. 7210. 
$ Bot. Mag. t. 7323. | Cheeseman (1906). 
