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amount of chlorophyll. The inner cortex consists of large 
groups of sclerenchyma separated by narrow bands of trans- 
lucent cells. The cortex of the youngest branches is green, 
but when the epidermis becomes filled with tannin’ the 
branch assumes a dark-brown surface which ultimately is 
ruptured by cork-formation. 
Alhagi Camelorum Fisch. 
One of the most common plants in Trancaspia. It looks 
like a stumpy shrub with green branches. The aerial parts, 
however, are not persistent and in general Alhagi is doubtless 
a root-geophyte. But as short stems are occasionally found 
— probably rhizomes originally — from which new shoots 
rise 10—30 centimetres above the ground, and as the 
determination of RAuNKLER’s biological types is dependent on 
the position of the least protected buds, I propose to classify 
the species under the chamaephytes. 
The light-shoot of Alhagi is green and spiny. The plant 
frequently assumes the globular form since the close-set 
expanded branches project equally in all directions. The 
leaves are small, at most a couple of centimetres long, 
oblong-ovate or spathulate, and the majority fall off during 
the early part of summer. This is especially the case with 
the leaves developed later, whereas many of the older, lower 
leaves persist for a long time. This is probably due to the 
great heat and dryness of the summer which prevents the 
perfect development of new leaves. 
All the leaf-axils except the very uppermost bear thorn- 
branches. These are leafless and green, about 4 centimetres 
long and with a yellow tip; only the upper thorn-branches 
bear flowers. These branches arise not in the middle of 
the leaf-axil but obliquely towards the cathodic side of the 
leaf (the phyllotaxy is a ”/5 spiral). Many of the leaf-axils 
of the main-shoot give rise to long-shoots beside the spine, 
on the anodic side; these long-shoots bear leaves which also 
subtend spines except sometimes the upper ones, more rarely 
they bear long-shoots. 
Alhagi has horizontal roots which at intervals send out 
