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October. Being light and provided with wings it is easily 
carried along by the wind. 
The leaves are centric in structure, of the type so often 
described, with a palisade layer and a starch sheath towards 
which the veins pass obliquely through the central aqueous 
tissue. (See VOLKENS p. 138). The vein is surrounded by 
sclerenchyma (fig. 39). 
Between the epidermis and the palisade cells is a layer 
of cells with very thin walls and large intercellular spaces 
(fig. 39 A and C). Some of them contain clusters of crystals, 
also described and illustrated by Vorkens (tab. XII, 3). 
This crystal-layer appears to be distinct from the epidermis 
but it may be compared with the corresponding one in Hal- 
oxylon (WARMING 1897 p. 218). where it is included amongst 
the epidermal tissues, and in both cases it may probably be 
regarded as a hypoderm; there must be air between its cells. 
In var. longifolia the leaves are perfectly cylindrical; in 
the stunted form they are often slightly concave or flat on 
one side. 
Salsola subaphylla C.A. M. 
A shrub or small tree attaining a height of about 2 
metres. It somewhat resembles the last species, but does 
not attain the same height, its foliage is less dense, and it 
sets fruit earlier. According to PALEZzKI its life-period does 
not at the most exceed four years, hence it is not employed 
for sand-binding purposes. It is by preference a sand-plant 
and attains its highest development where the sand is moving. 
On clay or stony soil it appears as a small shrub of about 
30 centimetres high. 
The leaves (fig. 13) are thick, cylindrical or half-cylindrical 
and attain the length of about two centimetres. 
The year-shoots are branched, sometimes twice. The 
distal parts of the year-shoots and branches are in the month 
of July covered with flowers (fig. 13) subtended by scale-like 
bracts; the fruit-bearing branches may be quite hidden 
under the broad wings of the numerous fruits. 
After the cessation of the vegetative period the tips and 
