When I first visited southern Algeria it seemed improbable that any portion of it, or at least any portion that I should be likely to see, would exhibit the possibilities of plant growth as unaffected by herbivorous animals. But finally there were found two classes of plant formations in which animals either had not intruded at all, or not to a harmful degree. One of these is the wide flood-plain of the Oued M’Zab, or one of its tributaries, lying about 50 kilometers east of Ghardaia. Despite the fact that the flocks are very numerous in the vicinity, and that the flood-plain is on the regular caravan route between Ghardaia and Ouargla, there are few signs of grazing. The entire plain is so well covered by shrubs that the vegetation gives the tone to the landscape—a rare thing in the desert. Here one finds _Retama retam_, _Genista saharæ_, and _Ephedra_ sp., as well as other species in fair abundance. Thus the plants are not only numerous, but are of a good size. It should be observed that on either side of the flood-plain, on the hamada, scarcely any vegetation may be found. The second formation referred to is that of protected areas, especially at Ghardaia, which have been little disturbed at any time, and portions of them not at all disturbed for centuries. These are the cemeteries. Such areas are situated not only in the floor of the M’Zab Valley, where the plant conditions are relatively favorable, but also on the hamada, where they are relatively very unfavorable. Both in the valley and on the hamada, as well as on the valley wall between the two wherever there chances to be soil, the plants are relatively numerous and of fair size. This fact has been detailed under the section on Ghardaia and need not be more than mentioned here.