220 APPENDIX. 



Respecting the distribution of the species within Mexico and Central America there 

 is little to be said beyond repeating the statement, made under the genera, that 

 Mexico is the only part which has been sufficiently explored to enable us to form 

 something approaching a correct estimate of the extent of its flora. But the figures 

 speak for themselves : 65 per cent, of the species, belonging to about 78 per cent, 

 of the genera, inhabit South Mexico, that is, including the " uncertain," which 

 we now find properly belongs to it. The botany of the Isthmus part of the Province 

 or State of Panama is also tolerably well known, though doubtless by no means 

 exhausted ; and the poverty of the flora of this region may be accounted for by the 

 very trifling elevation of the highest part. Notwithstanding the fragmentary nature of 

 our knowledge of the vegetation of some portions of Central America, what we do 

 know being partly the results of the labours of competent botanists like (Ersted and 

 Seemann, and partly of enthusiastic collectors such as Sutton Hayes, may be regarded 

 as a fair sample of the whole ; and future collections are not likely to invalidate, or 

 even greatly modify, the deductions to be drawn from the material from which our 

 Tables were constructed. It may be assumed, too, that a moiety at least of future 

 discoveries in the less explored districts will consist of species already recorded from 

 the neighbouring countries ; hence the total numbers of genera and species for the 

 whole area will not be so largely augmented as might at first be supposed. Still, 

 considering that our total number of species from Honduras and Salvador is only 160, 

 from Nicaragua less than 1000, and from Costa Eica about 1150, and that the 

 vegetation of these countries is reported generally as rich, it is, perhaps, a little 

 hazardous to advance the theory that comparatively few generic types remain undis- 

 covered. But the flora of Central America, so far as it is known, is so largely South- 

 American that we confidently expect that the additions will be mainly specific. 



This view is strengthened by a closer examination of the facts connected with the 

 extension of South-American genera and species into Central America and northward 

 into the tropical parts of Mexico. But before proceeding to the discussion of this 

 part of the subject, it may be as well to tabulate the percentages of species in each of 

 our primary divisions and subdivisions of Mexico and Central America and the extensions 

 beyond, as percentages give a much better idea of the relative proportions than mere 

 numbers. 



Numbers and Percentages of Endemic Species of Phanerogamic Plants in Mexico 



and Central America. 



Number. Per cent. 



Total endemic 8193 70-5 of 11626 



Endemic in North Mexico to Honduras 6693 



„ Nicaragua to Panama 1076 



„ the combined areas 424 



8193 100-0 



81-7 



of 



8192 



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