76 DR. WELWITSCH ON A SPECIES OF CISSUS. 
300 miles from east to west, commencing with the burning sandy 
steppes of the Atlantic coast region, and extending into the richly- 
wooded, cool, elevated plains of the interior. Throughout this 
space the number of species increases gradually, and the number 
of individuals becomes continually greater. With regard to their 
geographical distribution, it is found that the species with thick 
sappy fleshy stems preponderate in the littoral region (0-1000 feet 
alt.), those with elongated twining stems in the region of the 
primeval forests, and the species with upright, scarcely twining 
stems in the highest region of the elevated plains of the interior. 
Thus the species “caule stanti” are very rare in the littoral region, 
and are still more rare in the primeval-forest region, whilst almost 
all the species which are found in the region of the elevated plains 
exhibit a short upright stem, without any tendency to scramble 
or climb. 
A second characteristic accompanying the geographical distri- 
bution of the Angola species of Cissus is the hairy covering of the 
stem and leaves. The species of the littoral region for the most 
part exhibit bright green, only slightly hairy stems and leaves, 
whilst the species of the primeval-forest region are characterized 
by dark-green shining foliage and more or less leathery, some- 
times even evergreen leaves. On the other hand, in almost all 
the species of the region of the elevated plains, as for instance 
around Pungo-Andongo and Huilla, a thick hairy, or even felt- 
like, covering is seen on the stem and leaves. In a species 
which occurs upon the gneiss-rocks of Pungo-Andongo this latter 
covering forms such a thick golden-brown pile*, that the entire 
plant has the appearance of being hewn out of pure copper, and 
is indisputably one of the most beautiful of the vegetable produc- 
tions of Angola. I have (provisionally) called this lovely species, 
which I believe to be undescribed, Cissus Livingstoniana, wishing 
thereby to indicate the fact (so important for geography) of this 
distinguished traveller having once visited Pungo-Andongo. 
I purpose, with the kind permission of the Linnean Society, 
upon some other occasion, to lay before them this latter species, 
as well as the other notable forms or species collected by me in 
West Tropical Africa. For the present I confine myself to the 
description of a very remarkable species which occurs in the 
southernmost part of Benguella, in the district of Mossamedes, 
. the same region where the Welwitschia growsf. 
* Folia cupreo-velutina aureo-nitentia. 
+ The paper was accompanied by a living specimen (which has since flowered 
