camel's-thorn

from The Century Dictionary.

• noun A spiny leguminous shrub, Alhagi Maurorum, of which the camel is very fond, and which yields a manna-like exudation from its leaves and branches.
• noun Erroneously, a spiny rhamnaceous shrub, Zizyphus nummularia, of Persia and India, which bears an edible berry, and the leaves of which are used as fodder for sheep and goats.
• noun In South Africa, several species of Acacia which are browsed upon by the giraffe, especially A. Giraffœ and A. erioloba.