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.
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.
Besides the grasses there are leguminous plants valuable for pasture - Astragalus, Vicia (wild vetch), Lathyrus (wild pea) of which there are many species.
Some petioles are long, slender and sensitive to contact, and function as tendrils by means of which the plant climbs; as in the l,' nasturtiums (Tropaeolum), clematis and c in others; and in compound leaves the midrib and some of the leaflets may similarly be transformed into tendrils, as in the pea and vetch.
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.