The tendrils of a vetch and of a cucumber are analogous, and also homologous because they both belong to the category leaf; but they are only analogous to the tendrils of the vine and of the passion-flower, which belong to the category stem.
Upon the exposed mountain slopes a species of rhubarb (Rheum Ribes) is noticeable.
Besides the grasses there are leguminous plants valuable for pasture - Astragalus, Vicia (wild vetch), Lathyrus (wild pea) of which there are many species.
Besides wheat, the following crops are to a greater or less extent cultivated - barley, millet, sesame, maize, beans, peas, lentils, kursenni (a species of vetch used as camel-food) and, in some parts of the country, tobacco.
If these results are confirmed and the treatment can be worked commercially, the importance to agriculture of the discovery cannot be overestimated; each plant will provide, like the bean and vetch, its own nitrogenous manure, and larger crops will be produced at a decreased cost.
Dextro-asparagine was first found in 1886 in the shoots of the vetch (Piutti).