Pl. 4, fig. 11. Near view of the daya of Tilrempt. The fortified stage station, bordj, and a nomad camp are to be seen. The flattened, level, lower surface of the trees is the effect of grazing, mainly by camels. 12. Jujube (_Zizyphus_) shrubs and betoum (_Pistacia_) at the daya of Tilrempt. Pl. 5, fig. 13. A young specimen of betoum in the midst of a protecting jujube at the daya of Tilrempt. 14. Leaf and shoot habit of the jujube (_Zizyphus lotus_). Daya of Tilrempt. 15. Leaves of the betoum (_Pistacia atlantica_) from the daya of Tilrempt. Pl. 6, fig. 16. South wall of the valley of the Oued M’Zab at Ghardaia. 17. Detail of an eroded bank of the Oued M’Zab at Ghardaia. The overhanging stratum is hardpan similar to the “caliche” of southwestern United States. Pl. 7, fig. 18. Shoot-habit of _Haloxylon articulatum_, from the plain near the daya of Tilrempt. 19. Agriculture at Ghardaia. The fields are divided into plots about 3 by 4 feet in size, for the more economical use of water. Young barley is shown growing (November). Pl. 8, fig. 20. Vegetation in upper part of a “draw” on plain north of the M’Zab Valley, Ghardaia. 21. Situation of square No. 2, on plain north of valley at Ghardaia. Pl. 9, fig. 22. _Capparis spinosa_ at base of valley wall at Ghardaia. 23. Leaves of _Capparis spinosa_ from Ghardaia. Pl. 10, fig. 24. Leaf-habit of _Dæmia cordata_. Ghardaia. 25. Shoot-habit of _Salvia ægyptica_. Ghardaia. 26. Upper surface of rocks, showing small incrusting lichens, on a low mountain about 5 km. north of M’Zab Valley, Ghardaia. Pl. 11, fig. 27. Habitat of _Peganum harmala_, at Melika, Ghardaia. 28. Shoot and leaf habit of _Peganum harmala_, from Ghardaia. Pl. 12, fig. 29. Habit of _Henophyton deserti_ at Ghardaia when growing in a protected situation (cemetery). 30. Leaf-habit of _Henophyton deserti_. Ghardaia. Pl. 13, fig. 31. View in a cemetery at Ghardaia, to show the relatively abundant vegetation. 32. View in an M’Zabite cemetery, Ghardaia. _Haloxylon articulatum_ is the leading species shown. Pl. 14, fig. 33. Habit of _Deverra scoparia_, from plain about 3 km. north of M’Zab Valley, Ghardaia.