1919. ] Notes on the Vegetation of Seistan. 271 
stem, while in the other (luropus villosus). the flower-stem. 
and indeed the whole plant, is dwarfed. We will refer to the 
latter species again in discussing other types of vegetation. 
The leaves of most of the plants are very small, but the 
terminal twigs in a large proportion of the species (e.g. m most 
of those of Salsola) are swollen and fleshy. No plant was 
seen in which the main stem was of this nature. In a few 
species the leaves are broad and flat (e.g. Schweinfurthia sphae- 
rocarpa), while in several they are fairly large, thin and leathery. 
The best examples are Ruta sp and the Colocynt In Ww 
species the whole plant is thin and dry and has a remarkably 
withered appearance. This is most conspicuous in Salsola foetida 
and Halogeton ? glomeratus, in both of which the plant appears 
to be not only dead but bleached, and the only external sign 
of life is to be found in the green tinge that may be not 
on the lower surface of the base of the twigs 
Spines or thorns occur on a large proportion of the plants 
in this vegetation, but they are not all of the same nature. 
Those of Asti agalus gerensis, which are particularly long, strong 
and sharp and form dense radiating spheres or hemispheres 
protecting the fruit, are produced by a modification of the ra- 
chis of the leaves. When the leaf is young the rachis is green 
and tender. but it gradually hardens, the leaflets drop off and 
it is transformed into a remarkably formidable weapon of de- 
fence 
In this plant, as in several others, the flowers are situated 
only at the base of the leaves or on the lower surface of the 
branches, which spread out horizontally, protecting the flowers 
and seed from destruction by wind and perhaps assisting in 
fertilization by insects, which are by no means uncommon un- 
and directed upwards. 
The winds of Seistan are particularly violent and usually 
blow from the north-west. Protection against them is one of the 
chief needs of the desert plants, and this is provided for largely 
by the devices already noted. Its necessity is shown by the 
fact that it is only on the leeward side of little hills in the de- 
sert that there is any vegetation at all, and that plants are far 
more abundant in hollows than on the level, though there can 
seldom be any particular moisture in the former. 
th at Lab-i-Baring and at Hurmuk most plants are In dan- 
ger of destruction from grazing camels, against which thorns 
