Botanical features of the Algerian Sahara

Cannon William Austin 1870-

Sujets

• Botany
• Sahara

Informations

• Publié par: les_archives_du_savoir
• Nombre de lectures: 11
• Langue: English
• Poids de l'ouvrage: 10 Mo

Extrait

Digitized by the Internet Archive
in 2008 with funding from
IVIicrosoft Corporation
http://www.archive.org/details/botanicalfeatureOOcannuoftPLATE 1CANNON
X
s^'
^x^
kinds of wood,oak, pine, and otherrket at Laghouat. Jumper,F.g.
f-Tr,T^)a Io,tH .-xposed for sale.each bunch
andbranches of juniperLaghouat. Roots of Zizyphus,Fig. 3. Wood market at
used for staining.bark. The latter is said to bepine, and pineBOTANICAL FEATURES
OF THE
ALGEKIAN SAHARA
BY
WILLIAM AUSTIN CANNON
^^Y"^
V
WASHINGTON, D. C.
Published by the Carneqie Institution of Washington
1913CARNEGIE INSTITUTION OF WASHINGTON
Publication No. 178
(}y^\
Cl6
Bookof thisCopio&
issuedfirstwere
6 1913AUG
PRESS OF J. B. LIPPIKCOTT COMPANY
PHILADELPHIACONTENTS.
PAGE
Introduction i
Characteristics of AlgeriaGeographical 2
AlgeriaClimate of 6
Characteristics of the Vegetation of the TellSome 15
The Forests of Algeria 18
The High Plateau 20
Boghari to Laghouat 20
Djelfa to 22
Laghouat 23
The Oasis of Laghouat 24
The Plain 25
The Dunes near Laghouat 27
The Mountains about Laghouat 28
Effects of Grazing on Vegetation near Laghouat 29
From Laghouat to Ghardaia 31
Region of the Dayas 31
Daya of Tilrempt 32
The Chebka 34
Ghardaia 36
GhardaiaThe Oasis of 38
(Hamada) of GhardaiaThe Plain 39
aboutThe Mountains 41
the M'ZabThe Valley of 41
Areas near GhardaiaProtected 42
in the RegionRoot-Habits 44
Leaf-Habits in the Ghardaia 49
Growth and Flowering Habits in the Ghardaia Region 49
to Touggourt 50Ghardaia
to Ouargla—Vegetation 53—Ouargla to 56
to Biskra—Physical Features and VegetationTouggourt 58
RegionThe Biskra 59
Topography 59
Habitats of the Biskra Region 60Plant
Vegetation of the Biskra Region 61
Summary and Conclusions 66General
The Environmental Conditions of Plants in Arid Regions 66 Features of the Flora of Algeria 69
Some Effects of Temperature and Rainfall in Southern Algeria 71
The Soil Relation in Southern Algeria 73
Root-Characters and Species Distribution in Southern Algeria 76
The Biotic Factor 77
of Southern AlgeriaComparison of Some General Features of the Vegetation
and of Southern Arizona 79LIST OF ILLUSTRATIONS.
Plate A. Outline map of Algeria, showing main features of surface
drainage.
PI. I , fig. I . View of the oasis of Laghouat.
2. Wood market at Juniper, oak, pine, and other kinds of wood,
each bunch a camel load, exposed for sale.
market3. Wood at Laghouat. Roots of Zizyphus, branches juniperof and
pine, and pine bark. The latter is said to be used for staining.
PI. 2, fig. 4. Shoot-habit of Acanthyllis tragacanthoides. Laghouat.
5. of Zollikoferia spinosa. Laghouat.
6. Acanthyllis tragacanthoides on sandy plain.
7. Zollikoferia spinosa in habitat, plain (hamada). Laghouat.
PI. 3, fig.^ 8. Detail of north slope of Nomad Mountains, where Zollikoferia spinosa
theis dominant species. Laghouat.
9. Vegetation of plain (hamada) at Tilrempt. The conspicuous shrub is
Haloxylon articulatum.
10. The daya of Tilrempt from the plain, showing the character of the
depression.
PI. 4, fig. II. Near view of the daya of Tilrempt. The fortified stage station, bordj,
and nomada camp are to be seen. The flattened, level, lower surface
of the trees is the eflfect of grazing, mainly by camels.
{Zizyphus)12. Jujube shrubs and betoum (Pistacia) at thedaya ofTilrempt.
young specimenPL 5, fig. 13. A of betoum in the midst of a protecting jujube at the
of Tilrempt.daya
and14. Leaf shoot habit of the jujube (Zizyphus lotus). Daya of Tilrempt.
Leaves of the betoum [Pistacia15. atlantica) from the daya of
PI. 6, fig. 16. South wall of the valley of the Oued M'Zab at Ghardaia,
Detail of an eroded17. bank of the Oued M'Zab at Ghardaia. The over-
hanging stratum is hardpan similar to the "caliche" of southwestern
United States.
Shoot-habit HaloxylonPI. 7, fig. 18. of articulatum, from the plain near the daya of
Tilrempt.
Agriculture at Ghardaia. The fields are divided into plots about19. 3 by 4
feet in size, for the more economical use of water. Young barley is
shown growing (November).
fig. 20. Vegetation in upper part of a "draw" on plain north of the M'ZabPI. 8,
Valley, Ghardaia.
21. Situation of square No. on plain north of valley at Ghardaia.2,
22. Capparis spinosa at base of valley wall at Ghardaia.PI. 9, fig.
Leaves of Capparis spinosa from Ghardaia.23.
Leaf-habit of Dcemia cordata.PI. 10, fig. 24.
Shoot-habit of Salvia agyptica.25.
26. Upper surface of rocks, showing small incrusting lichens, on a low moun-
tain about km. north of M'Zab Valley, Ghardaia.5
II, Habitat of Peganum harmala, at Melika,PI. fig. 27.
28. and leaf habit of Peganum harmala, from Ghardaia.Shoot
fig. Habit of Henophyton deserti at Ghardaia when growing in a protectedPI. 12, 29.
situation (cemetery).
Leaf-habit of Henophyton deserti. Ghardaia.30.
View in cemetery at Ghardaia, show the relatively abundant vege-PI. 13, fig. 31. a to
tation.
View in an M'Zabite cemetery, Ghardaia. Haloxylon articulatum is the32.
leading species shown.
PI. fig. Habit of Deverra scoparia, from plain about km. north of M'Zab Valley,14, 33. 3
Ghardaia.
Root-habit of Gymnocarpos fruticosum, from plain about km. north of34. 3
M'Zab Valley at Ghardaia.
PI. fig. of a mature specimen of Peganum harmala, from the floor of15, 35.
the M'Zab Valley near Ghardaia. The soil at the place is compara-
tively deep.