— 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 
RS 2. C 
N Wu SION ESS 
| 
d 
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. D, Transverse section of a sandshoot 
(rejuvenescence-shoot); a, pith; b, wood; c, inner cortex; d, outer cortex 
(cork). E, 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 41/2 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 
