TEOPICAL FLORAS 61 



anists who alone could adequately cope with the work is com- 

 paratively so small, that it is not surprising to find thai the 

 great forest region of tropical America is still very imperfectly 

 known. Only tw^o considerable areas have been systematically 

 collected and studied — in ^orth America the entire tropical 

 portion from South Mexico to Panama commonly known as 

 '" Central America " ; and in South America the vast areas of 

 Brazil, itself comprising more than half of tropical South 

 America. The comparatively easy access to this latter country, 

 the attraction of its gold and diamond mines, its extensive 

 trade with England and with other civilised countries, have 

 all led to its being explored by a long series of botanists and 

 travellers, the result of whose labours have been incorporated 

 in a moniimental work, the Flora Brasiliensis of Martins, re- 

 cently completed after more than half a century of continuous 

 labour. 



The number of species described in this work is 22,800, an 

 enormous figure considering that its area is less than half that 

 of tropical Africa, and that probably two-thirds of its surface 

 has never been thoroughly examined by a botanist. The Cen- 

 tral American flora, as described by Mr. Hemsley,^ in less 

 than one-third of the area of Brazil has about 12,000 species, 

 and this is no doubt a much nearer approach to its actual num- 

 bers than in the case of Brazil. 



As regards the additions that may yet be made to that flora, 

 and especially to the great forest region of adjacent countries, 

 I will quote the opinion of a very competent authority, the late 

 Dr. Bichard Spruce, who assiduously studied the flora of the 

 Amazon valley and the Andes for fourteen years, and himself 

 collected about 8000 species of flowering plants, a large pro- 

 portion of which were forest-trees. In a letter to Mr. Bentham 

 from Ambato (Ecuador), dated 22nd June 1858, he writes: " I 

 have lately been calculating the number of species that yet 

 remain to be discovered in the great Amazonian forest from 



1 See Biologia Centrali Americana, by Messrs. Godman and Salveri; 

 Botany, 4 vols., 1888. 



