The sentiments of the residents of Ghardaia, which led to the establishment and protection of the cemeteries, made a close botanical study of them injudicious. Enough was seen, however, to establish several points, the most important being, at least for the areas considered, that there is growing in them, without irrigation, a somewhat rich flora composed of relatively large perennials. And from this fact it seems probable, if also protected against the predatory attacks of animals, that other areas under the present rainfall and other physical environmental conditions now obtaining would support a much heavier vegetation than is generally the case. How far the presence of man and of his flocks has otherwise modified the flora, especially as regards its composition, is another question, but it certainly has not been without its effect. In the portions of the M’Zab region, except certain areas rather remote from the towns, where there is no protection, the only forms which are at all abundant, or at least conspicuous, are such as are armed, poisonous or distasteful, or too small for use as fuel. Among these are _Peganum harmala_, _Zilla macroptera_, _Tamarix_, and others seen later. However, _Haloxylon articulatum_, although eaten by all animals so as never to develop in a normal manner, is surprisingly abundant, although by no means conspicuous. ROOT-HABITS IN THE GHARDAIA REGION. Owing to the small amount of soil, close observation of the root-systems of the plants growing on the mountains and the plain was difficult; examination of the roots in the field was therefore carried on mostly in the valley, although enough was seen of the roots of plants in the other habitats to permit a characterization of them. The roots of several species growing on the hamada close to the valley were examined with the following as the leading results: _Deverra scoparia_ was found to have a main root running directly downward 20 cm. without giving off large laterals; at that depth it forked, the resultant branches running thereafter in a horizontal direction. (See fig. 33.) _Teucrium pseudo-chamæpitys_, _Centaurea pubescens_, and _Salvia ægyptica_, all from the hamada to the north of the M’Zab Valley, have pronounced main roots. A similar type of root was seen in _Zollikoferia resedifolia_ and _Fagonia bruguieri_ from the plain to the south of the valley. Grasses growing on the plain had roots which, as usual with grasses, showed more diversity, but on the whole penetrated rather deeply. The root-system of _Haloxylon articulatum_ is of the modified generalized type, penetrating deeply also, and will be best described as an inhabitant of the valley.