GEOGRAPHICAL AND GEOLOGICAL BOTANY. 



Characteristic genera. Straeniia, Maerua, Semea, Oncoba, Caucanthus, 

 Geruma, Balsamodendron, Cadia, Orygia. Some approximation to tlie 

 South- African flora (Stapelia, Haernanthus). 



Predominant trees and shrubs. Pandanus odoratissimus, Ficus Svca- 

 morus, F. salicifolia, F. populifolia, F. Forskalii, F. palmata, F. serrata, F. 

 Sur, F. Toka, Avicennia tomentosa, Cynanchuni arboremn, Balsamoden- 

 dron gileadense, B. Opobalsamum, B. Kataf, B. Kaful, Celastrus edulis, 

 C. parviflora, Grewia populifolia, Maerua unifiora, M. racemosa. 



Cultivated plants. Millets (species of Sorghum), six-rowed Barley, 

 Maize, Arum Oolocasia, Date-palm, Plantain, Cocoa-nut, Tamarind, Fig, 

 Papaw, Peach, Apricot, Plum, Apple, Quince, Vine, Coffee, Sugar, Ginger, 

 Radish, Spinach, Gourd, Dolichos, sp., Tree-cotton, Indigo. 



Note. This region extends to the plains of North-east India (Scinde), 

 and should probably include part of Persia and also of the Abyssinian 

 region. (Boissier's ' Flora Orientalis ' is a most valuable book on the 

 flora of these regions. See also Cosson's memoirs.) 



13. The Desert Eegion (Delias Region). 



Mean temperature, 73-86 Fahr. (23-30 C.). 



Character. This region, like the preceding, is subject to the unchecked 

 prevalence of trade-winds. It varies in character according to the rocky 

 or sandy character of the plains, the presence of oases, &c. A very p^oor 

 flora. No characteristic Orders or genera, but the following species : 

 Pennisetum dichotomum, Phoenix dactylifera, Cucifera thebaica, Euphor- 

 bia rnauritanica, ^Erua tomentosa, Acacia nilotica, A. arabica, A. gummi- 

 fera, A. Senegal, Cassia obovata, C. Singueana, Alhagi mauronim, Mimosa 

 Habbus, Zizyphus Palma Christi, Zygophyllum simplex, Z. album, Fago- 

 nia arabica, F. Oudneyi. 



Cultivation. Only in the Oases; here principally the Date-Palm. 

 Doura (Sorghum vulgare), Wheat, Barley. South-European and certain 

 [ndian fruits. 



14, Region of Tropical Africa (Adansoris Region). 



Mean temperature, 73-8G Fahr. (23-30 C.). 



Character'. The Sudan region of Grisebach ; is remarkable for the large 

 number of peculiar generic types, each often containing but few species. 

 Leguminosae, Rubiaceae, Cyperaceae very prevalent. Comparatively few 

 species of Palmaceas, Filices, Scitamineaa, Piperaceae, Passifloreae. 



Genera. Adansonia, Dombeya, Melhania, Christiania, Pentadesma, 

 Napoleona, Parkia, Thonningia. 



Predominant trees and shrubs. Anona senegalensis, c., Cadaba fari- 

 nosa, Crataeva Adansonii, Capparis edulis, Pentadesma butyracea, Bom- 

 bax pentandrum, B. guineense, Adansonia digitata, Sterculia acuminata, 

 Grewia carpinifolia, Acacia, sp., Cassia occideutalis, Pterocarpus esculen- 

 tus, Parkia africana, Chrysobalanus Icaco, Conocarpus pubescens, Rhizo- 

 phora, sp., Psychotria, sp., Bignonia tulipifera, Avicennia africana, Eu- 

 phorbia (shrubby species), Ficus, sp., Elais guineensis, E. nielanococca, 

 Rhapis vinifera, Phoenix spinosa, Pandanus candelabrum. 



