220 



light-shoots directed upwards. Normally these die during 

 winter down to the surface of the soil and new shoots appear 

 next year from the upper part of the subterranean perennial 



Fig. 50. Alhagi Camelorum. A, Leaf in transverse section. B, Part of a 

 transverse section of the outer cortex of a thorn shoot. C, Part of trans- 

 verse section of a young shoot. Z), Transverse section of a sandshoot 

 (rejuvenescence-shoot); a, pith; b, wood; c, inner cortex; d, outer cortex 

 (cork). Ej The outermost part of the outer cortex in D. D: slightly 

 magnified; the others. X 203. Cells containing tannin are hatched. 



rhizome. These as well as old roots (?) may become very 

 thick; I have seen them 4 L /2 centimetres in diameter. 



From what has been already said, it will be understood 

 that the Alhagi are gregarious plants, and that their subter- 

 ranean parts contain food-reserves which enable them to 

 contend against very unfavourable conditions. Alhagi has 



