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.
34. Root-habit of _Gymnocarpos fruticosum_, from
plain about 3 km. north of M’Zab Valley at
Ghardaia.
Pl. 15, fig. 35. Root-habit of a mature specimen of _Peganum
harmala_, from the floor of the M’Zab Valley
near Ghardaia. The soil at the place is
comparatively deep.
Pl. 15, fig. 36. Root-systems of _Helianthemum sessiliflorum_
(right), _Haloxylon articulatum_, and _Nolletia
chrysocomoides_ (left), from the flood-plain of
the Oued M’Zab, Ghardaia.
Pl. 16, fig. 37. Shoot and root habit of _Citrullus colocynthis_.
Oued M’Zab, Ghardaia.
38. _Euphorbia guyoniana_, in the valley of the Oued
M’Zab at Ghardaia.
Pl. 17, fig. 39. Habit of _Euphorbia guyoniana_. Ghardaia.
40. To the left, shoot of _Centaurea_ sp., showing
effect of grazing; to the right, shoots of
_Teucrium pseudo-chamæpitys_. From Ghardaia.
Pl. 18, fig. 41. Habit of _Salsola_ sp. (below) and _Echinopsilon
muricatus_, from the M’Zab Valley, Ghardaia.
42. Ghardaia to Ouargla. View overlooking the hamada
about 28 km. from Ghardaia. The relatively
abundant vegetation is associated with a
light cover of sand over the area shown. The
leading species are _Aristida_, _Deverra_, and
_Haloxylon_.
Pl. 19, fig. 43. _Retama retam_, in dunes about 58 km. from
Ghardaia.
44. Dates at the Bordj Zolfana, about 58 km. from
Ghardaia—one of two wells encountered between
Ghardaia and Ouargla.
45. Ghardaia to Ouargla. View overlooking flood-plain
of the Oued M’Zab, or a tributary of this oued.
The adjacent upland is apparently without
plant life.
Pl. 20, fig. 46. Vegetation on edge of the Oued M’Zab, about
63 km. east of Ghardaia, showing habitat of
_Rhantherium adpressum_ in foreground.
47. Sandy flood-plain of the Oued M’Zab, about 63
km. from Ghardaia. _Retama_, _Genista_, and
_Ephedra_ are the leading plants in this place.
48. Habit of _Ephedra alata_ in habitat shown in
figure 47. This specimen was 1.5 m. high.
Pl. 21, fig. 49. View of habitat of _Ephedra alenda_, 138 km. from
Ghardaia.
50. Detail of suckering habit of _Ephedra alenda_,
from habitat shown in figure 49.
Pl. 22, fig. 51. Vegetation, mainly _Ephedra_ and _Retama_, of the
western edge of the Chott Mellala.
52. Approach to western edge of the Chott Mellala,
showing characteristic rounded hills, or
mamelons.
Pl. 23, fig. 53. View between the Ouargla plain and the Chott
Mellala, showing characteristic appearance of
eroded hills.