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in T. hispida. All the cells of the single-layered epidermis 
are distinctly convex and papilla-like. The stomata on the 
upper and lower surfaces, and the salt-glands are sunk. One 
layer of palisade cells all round is present both in the leaves 
and the assimilating branches. The leaf also has rather open 
spongy parenchyma and veins with a bast-sheath besides 
storage-tracheids (“Speichertracheïden”). 
I have not investigated in detail the more mesophytic 
fanerophytes (Elaeagnus, Ulmus, Morus, Populus, Salix). 
Elaeagnus hortensis was observed in August with two series 
of branches on the year-shoot, but this does not appear to 
be the rule. The same holds good with regard to Salix 
angustifolia. The species of all the genera just mentioned 
flower in spring. 
The above Fanerophytes have the following characteristics 
common to all or some of them. 
The leaves are greatly reduced. In one set of species 
they take no part as assimilating organs (Eremosparlon, Calli- 
gonum, Ephedra, Haloxylon, Halostachys, Halocnemum), while 
in others they are scale-like, but green (Tamarix, Reaumuria 
fruticosa). Astragalus has leaves which are wholly or partly 
shed during summer, but whether as in the case of Spartium 
junceum (according to BERGEN), there is no assimilation or 
at any rate very little after. the leaves are shed, I cannot 
say, and one can scarcely draw a conclusion from a single 
case. Ammodendron, Halimodendron and Smirnowia have 
persistent, small, hairy leaves, while Prosopis, Atraphaxis, 
Lycium, Nitraria and Reaumuria oxiana have persistent small 
and glabrous leaves. The Salsola species have cylindrical 
persistent leaves. 
The leaves in Salsola and the assimilating shoots in the 
leafless species are all centric in structure, the latter in most 
cases have abundant mechanical tissue. 
In the flat-leaved species the leaves are wilhout excep- 
tion isolateral in structure. 
The branches in most sand-desert species are slender, 
