171 



finish the aerial period of their life before the end of June 

 and thus belong to the mesophytic aspect of the vegetation, 

 whereas many Rhizome -geophytes are very xerophytic e. g. 

 Heliotropium, Cresset, Aristida, Elymus, Dodartia. The Irises 

 and some others are mesophytic. 



The natural order Liliaceae consists entirely of geophytes. 

 (Table 5). The grasses include some very important and 

 characteristic desert-forms of geophytes: Aristida, Elymus, 

 Aeluropus and several species on the river-banks e. g. Phrag- 

 mites, Saccharum, Calamagrostis pseudophrag mites. The Borra- 

 ginaceae include important species of Heliotropium. Most of 

 the orders have no geophytes at all. (Table 5). 



There are few Chamaephytesin the Transcaspian desert. 

 Assuming that the classification of growth-forms is correct, 

 52 species belong to this type, all undershrubs with the 

 exception of Nanophytam erinaceum, which is rather a 

 cushion-plant. The aerial shoots of such chamaephytes die 

 back until near the surface of the soil, and the buds for 

 rejuvenation are situated at the base of the lignified and 

 persistent stems. This is also the case with Capparis spinosa 

 and Hulthemia berberifolia, but the shoots of these lie pro- 

 strate on the ground as in the more typical chamaephytes. 



The species given in the list as Chamaephytes are 

 generally desert-plants, with green shoots which live through 

 the whole summer and contribute to the xerophytic aspect. 

 More than half of them at least 29 flower after July 1. 

 Some species play a rather prominent part in the desert, 

 thus Anabasis salsa, Arthrophytum, Noaea spinosissima, Arte- 

 misia, Convolvulus erinaceus and fruticosus, Alhagi, Psoralea 

 drupacea, Hulthemia berberifolia , Haplophyllum obtusifolium, 

 Reaumuria squarrosa and Stellera Lessertii. These chamae- 

 phytes seem to have attained a high degree of adaptation to 

 desert-life. The generally follow the clay-soil although some 

 of them appear on the less fugitive sandy soils (Convolvulus 

 erinaceus). 



Although there are relatively few Chamaephytes in the 

 Transcaspian desert (7 per ct.), they are far more numerous 

 there than in temperate countries. Denmark for instance 

 has only 3 per ct. But if we go southwards from Transcaspia 



