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tumn vegetation is similar in the two forms of desert there 

 is no reason for distinguishing between "Clay-desert" and 

 "Loess-steppe", as has been done by Antonow. 



In the middle of May the Semi-desert is already be- 

 ginning to turn yellow, and many of the spring-plants have 

 even dispersed their seeds in April. Towards the end of May 

 almost all the plants of non-xerophytic structure have withered 

 or are withering rapidly, and the summer-plants make their 

 appearance. Our illustration (fig. 4) shows the rolled-up 

 withered yellow leaf-rosettes of Ferula Asa foetida, while 

 many grej' Artemisia bushes are not yet in bloom. The sur- 

 face soil in this place was cracked by drying, but at a depth 

 of 7 centimetres the loess was still dark with moisture. Thus 

 it seems to be the dryness of the air rather than that of the 

 soil which kills the spring-vegetation. 



As June advances, any spring-plants left become so dry 

 and brittle that they fall to pieces when touched. They soon 

 disappear entirely and then the semi-desert becomes a true 

 desert similar to the claj^-desert proper. The two desert forms 

 will therefore in what follows be treated together under the 

 latter designation. 



The surface in places is perfectly bare, but as a rule it 

 is spotted over by scattered summer-plants. Generally only a 

 single species or very few species occur together in each 

 locality, different ones in the different places. The number of 

 summer-plants is extremely limited, and a review of them 

 is soon made. 



Artemisiae often constitute the whole of the summer- 

 vegetation; BoRSzczow records A. fragrans and monogyna, 

 but specimens I brought home were identified as A. herba 

 alba. In any case the species are closely related to A. mari- 

 tima: silver-white, aromatic undershrubs, strongly branched 

 at the base. This mode of growth (a "Wermuth-Steppe") is 

 seen in the illustration (fig. 4), and it may be uniform over 

 large areas. 



In other places Salsola rigida is the principal species. 

 Its growth-form is between a shrub and an undershrub, half 

 a metre high, dry and twiggy in appearance, and generally 

 with many dead branches; its leaves are rigid and cylindri- 



