io8 PLANT GEOGRAPHY 



AFRICA. The ancient, long consolidated, undisturbed, 

 and isolated continent of Africa is as remarkable for the 

 elements that are absent from its flora as for what it 

 possesses. As the " Scandinavian " forms have not got 

 across the Mediterranean to the Atlas Mountains, so 

 neither do the European Miocene types seem to have 

 reached it. It has neither Magnoliacece nor Maples, no 

 Rhododendron, Vacciniacece, Pomacece, or Quercus. It 

 has fewer Bamboos, Orchids, and Aroids than other 

 tropical areas; and, though two of its Palms (Phcenix 

 dactylifera L. and Ela'eis guineensis Jacq.) are familiar 

 for their economic products, and the tribe Bovassece is dis- 

 tinctively African, this group also is less well represented 

 than it is either in Tropical Asia or Tropical America. 

 Invasion from the east, presumably along the Mascarene 

 bridge, has been more effective than from the north, and 

 is represented in East Africa by the Indian Gloriosa, the 

 palm liane Calamus, and, perhaps, by Phoenix. 



One of the most marked facts connected with the 

 flora of this continent is the wide range both in latitude 

 and longitude of many of its species. No less than 

 one-fifth of the Tropical species are common to East 

 and West; whilst the range of the Trumpet- or Pig-lily 

 (Zantedeschia cethiopica Spreng.), from Cape Town to 

 the First Cataract of the Nile, is the botanical parallel 

 of the wide latitudinal range of the Hippopotamus. 



In East Africa a large area is occupied by Savannah- 

 forest, in which occur scattered plants of Euphorbia and 

 Aloe, with many herbaceous species; and by Thorn- 

 forest, in which are numerous Acacias and Albizzias, with 

 few herbaceous plants, but with many slender twining 

 species and a few epiphytic forms of Peperomia and 

 Angrcecum. 



In the west of the continent, on more retentive soil, 

 we have the savannah of Loango, with lofty grasses, such 

 as Andropogon and Cymbopogon, ten feet in height; a 

 few low-growing shrubs, such as species of Anona ; 

 Palms, such as Borassus flabellifer L. and Ela'eis; and 

 the gigantic water-storing Baobab (Adansonia digitata 

 L.). This passes southward into the stony deserts of the 

 Kalahari Region that extend across the Southern Tropic, 

 where Palms cease ; but, with spinous Acacias and some 

 bulbous species, in the loose sands occur the striking 

 cucurbitaceous shrub the Naras (Acanthosicyos horrida 



