98 PHYSIOGNOMY OF PLANTS. 



gamia, only 10042 species. Willdenow, in his edition of 

 the Species Plantaruin, between the years 1797 and 1807, 

 had already described 17457 phsenogamous species, (from 

 Monandriato Polygamia dioecia.) If we add 3000 cryptoga- 

 mous species, we obtain the number which Willdenow men- 

 tions, viz. 20000 species. More recent researches have shown 

 how much this estimation of the number of species described 

 and contained in herbariums fulls short of the truth. Ro- 

 bert Brown counted above 37000 phsenogamous plants. 

 (General Remarks on the Botany of Terra Australis, p. 4.) 

 I afterwards attempted to give the geographical distribution 

 (in different parts of the earth already explored), of 44000 

 phsenogamous and cryptogamous plants. (Humboldt, de 

 distributione geographica Plantarum, p. 23.) Decandolle 

 found, in comparing Persoon's Enchiridiuni with his Uni- 

 versal System in 12 several families, that the writings of 

 botanists and European herbariums taken together might 

 be assumed to contain upwards of 56000 species of plants. 

 (Essai elementaire de Geographic botanique, p. 62.) If 

 we consider how many species have since that period been 

 described by travellers, (my expedition alone furnished 

 3600 of the 5800 collected species of the equinoctial 

 zone), and if we remember that in all the botanical 

 gardens taken together there are certainly above 25000 

 phsenogamous plants cultivated, we shall easily perceive 

 how much Decandolle' s number falls short of the truth. 

 Completely unacquainted as we still are with the larger 

 portions of the interior of South America, (Mato-Grosso, 

 Paraguay, the eastern declivity of the Andes, Santa Cruz 



