FLORA OF ADEN . 
41 
neighbouring Socotra the vegetation shows the following proportion : 
1 :4 : 7 . 
This seems to indicate that the paucity of species in the flora of 
Aden is not the result of situation or isolation, but the necessary con- 
sequence of the meteorological factors combined with unfavourable 
edaphic conditions. The vegetation has to strive against conditions tend- 
ing to the entire extinction of vegetable life, viz. excessive heat and 
drought. It is probably owing to this fact that no less than 19 orders 
are represented by only one species, 11 by 2, and 9 by 3. 
Of the 250 species 47 are Monocotyledons, the majority, viz,, 33, 
belonging to the Gramineae. Of Dicotyledons there aie 202 species, 
i e., about 4 of the whole flora. The predominant orders are the Legu - 
minosce with 32 species, the Capparidacece, with 18, the EuphorbiacecR 
with 13, the Boraginacea and Ckenopodiacece with 11, the Composite 
with 10, and the ScrophiUariacece with 9. The flora is composed of 136 
herbs, 46 undershrubs, 58 shrubs, and 10 trees. We give in the follow- 
ing a complete list of all the species reported from Aden, indigenous as 
well as introduced. The names printed in italics indicate that the res- 
pective species is not indigenous in Aden. The record of the plants 
observed in Little Aden is very incomplete Defiers says that most 
plants growing in Aden occur likewise in Little Aden. 
Explanation of abbreviations : 
A. = Arbor, tree. H. = Herba, herb. 
F. = Frutex, shrub. a. = annual. 
8. = Suffrutcx, undershrub. p. = perennial. 
b = biennial. 
Order. 
Genus. 
Species. 
End 
Sr 
^3 
a 
i— i 
Introd. 
Aden. | 
< 
<D 
-IJ 
Sh. Oth. 
— 
Menisp^rmacese 
Cocculua 
cebatha DC. . 
X 
... 
X 
... 
F. 
Crucifer re 
Farsetia 
longisiliqua Dene. . 
X 
... 
X 
... 
S. 
Diplotaxis 
pendula DC. 
X 
... 
X 
... 
H. 
Capparidacose 
Cleome 
quinquene rvia DC. 
X 
... 
X 
... 
... 
S. 
papillosa Steud. . 
X 
X 
... 
H. p. 
bravhycsrpa Vahl 
X 
X 
.. 
H. p. 
paradoxa E. Br. 
X 
... 
X 
... 
S. 
pruinosa Anders. • 
X 
... 
X 
... 
... 
S. 
braohystyla Defl. . 
... 
X 
... 
X 
... 
s. 
I 
