— 170 — 
In Transcaspia the conditions are just the reverse. As 
may be seen from table 1 (p.17), the precipitation is greatest 
in winter so that the coldest season is comparatively humid. 
In this respect the climate to a certain degree favours 
the growth of trees. But as a whole it is only to a slight 
degree favourable! The long dry period which occurs during 
the vegetative period for trees necessitates the utmost economy 
as regards water. Therefore only the more xerophytic trees 
are able to live; their external and internal structure will be 
described below (chap. 13). 
Fanerophytes occur in comparatively few of the natural 
orders represented in Transcaspia (Table 5). For instance 
in Borraginaceae, Caryophyllaceae, Cruciferae, Labiatae, Ranun- 
culaceae and Umbelliferae they are totally absent. On the 
other hand, the numerous species of Tamarix and Calligonum 
have this effect that the Tamaricaceae and Polygonaceae 
consist mainly of trees and bushes. The species of Calli- 
gonum are more especially true desert-plants. Many of the 
fanerophytic Papilionaceae (Astragalus, Ammodendron, Ere- 
mosparton) and Chenopodiaceae (Salsola, Haloxylon), are like- 
wise true desert plants, xerophytic in structure. On the 
contrary the only two fanerophytic Compositae (Artemisia 
procera and Zollikoferia acanthodes) are unimportant species, 
rarely recorded. 
The 10 per ct. of Geophytes in the Transcaspian desert 
is a rather high figure compared with the “Normal - Spec- 
trum”, but it is in agreement with Samos and Cyrenaica 
(Table 3). Of the 72 geophytes, 33 (46 per ct.) are rhizome- 
plants, 24 (33 per ct.) are bulbous plants, 9 tuberous plants 
(13 per ct.), and 6 parasites (8 per ct., Orobancheaceae). 
As far as known only 5 geophytes may be found flowering 
after July 1. Only one of these Eremurus Olgae is a bulb- 
ous plant. The others (Tournefortia sibirica, Pluchea caspica, 
Cressa crelica, Saccharum spontaneum) have rhizomes. The 
term early flowering when applied to the rhizome-geophytes 
does not indicate that the epigeal shoots die after that time, 
for they continue to vegetate e. g. in Heliotropium Radula 
and chorassanicum, Acroptilon, Dodartia, Aristida and Elymus. 
Bulbous and tuberous plants, on the contrary, almost all 
