THE DESERTS OF WESTERN EGYPT 



297 



Arislida plurnosa is a perennial grass with short heavy stems 

 abundant in sandy wastes in which some scant supply of moisture 

 comes from below. ^Miniature accretion mounds or dunes are 

 formed b}' the action of the wind against its clumps. The blades 

 of the leaves are revolute and roll up so strictly that they appear 

 to be C3'lindrical, and as they are short and stiff the plant presents 

 a spinose aspect (see cross section of leaf of Arislida by Tschirch, 

 reproduced in Schimper's Plant Geography, p. 615, 1904). Al- 

 though noted from mam' places in northern Africa and As a this 

 plant was encountered in but one place and that between the oases 

 of Farafra and Baharia (?ee Fig. 4). 



CaUigonum comosum (Polygonaceae) is a small shrub 2 to 4 

 feet in height, which is abundant in northern Africa, and was seen 

 in the same locality as Aristida. This plant has been characterized 

 by Volkens as having extremely long and deeply penetrating roots. 

 No time could be devoted to excavation to test this matter and 

 the conclusions of this author seem to have been arrived at de- 

 ductively. 



Caryoxylon foetidum Moq. (SaUola foetida Del) (Chenopodia- 

 ceae) is a shrubby perennial 2 to 3 feet in height, the younger 

 branches of which present the characteristic aspect of the salsolas. 

 It is abundant in sandy ground in the greater depressions in 

 northern Africa and Asia. The camel-drivers apphed the term 

 "Khreyt" to it, but it was found that this word was used loosely 

 to denote almost any plant eaten by a camel. 



Cistanche lutea (Orobanchaceae) was found in the vicinity of 

 more than one host, and its pm'plish scales and yellowish flowers 

 make it a conspicuous object in places where the colors are gray 

 or dull. Bedouins appear to boil the fleshy stems and use the 

 decoction as a medicine, it being known to them as "Haluk." 



Farsetia aegyptica var. ovalis (Cruciferae) or "Garba" is a small 

 shrub 1 to 2 feet in height with narrow, inear leaves, inhabiting 

 sandy places and among rocks in northern Africa and southwestern 

 Asia. 



Haloxylon Schweinfurthii (Chenopodiaceae) is a small shrub 

 branching from the base, the branches being jointed and pale 

 yellow. Their thickness suggests succulence at certain times, 



