196 WEST AFRICAN FORESTS AND FORESTRY 



Stylochiton Dalzielii, Amorphophallus Barteri and A. dracontioides, 

 Anchomanes Dalzielii, and other species. 



Cyperace^ by very numerous species of Cyperus, e.g. the edible 

 Aya, C. esculentus, and the uncultivated Aya aya, C. rotundus, C. 

 Fenzelianus, etc., and several of Pycreus, Fimbristylis, Kyllingia, 

 Bulbostylis, etc. 



Gramine^ by the predominant tribe, Andropogonece, with numerous 

 other genera — Eragrostis, Aristida, Digitaria, Pennisetum, Chloris, etc., 

 and by a single locally distributed bamboo, Oxytenanthera Abyssinica. 

 The chief cereal is Guinea Corn, Dawa, Sorghum vulgare ; both 

 species of sugar-cane, Rake, Saccharum officinarum, and Takanda, 

 Sorghum vulgare, var. saccharantum, are cultivated. 



The FiLiCES are poorly represented by the widely distributed 

 Adder's Tongue, Ophioglossum vulgatum, the water-fern, Cratopteris 

 Thalictroides, by Adiantum lunulatum, A. Schiveinfurthii, and a few 

 species of Nephrodium asplenium, etc., by no means typical of the 

 region. 



Having thus given a bird's-eye view of the floral composition in 

 the central region of Hausaland, one may proceed to examine the 

 variations revealed in passing south to the semi-evergreen forests 

 and north to the drier open savannahs. 



Southwards the transition is gradual, and nowhere abrupt, from 

 forest savannah with annual bush -fires and consequent tendency to 

 revert to grass, to forests in which the number of species is greater and 

 the deciduous element is more mingled with evergreens, either by the 

 persistence of species which in a drier region are deciduous, but retain 

 their foliage where the increased rainfall allows of this variation, or 

 by the appearance of species which always possess the evergreen habit. 

 Bombax buonopozense is an example of the former and probably also 

 Afzelia Africana and several others. 



Some of the added constituents either absent from or more rare 

 in the area of lesser rainfall are : 



Anonace^ : Xylopia parviflora, Hexalobus Senegalensis, Popowia 

 Mannii. 



Capparidace^ : Ritchiea sp., Capparis viminea, etc. 



BixiNE^ : Oncoba spinosa. 



Sterculiace^ : Cola laurifolia. 



Rutace^ : the Fasa kwari, Zanthoxylum Senegalense. 



Meliace^ : Trichilia retusa. 



Anacardiace^ : Spondias lutea, Hcematostaphis Barteri, and the 

 cultivated mango. 



Sapindace.^ : Blighia sapida. 



CoNNARACE^ : Scrambling shrubs, e.g. species of Agelcea and 

 Cnestic. 



