292 PHYSIOGNOMY Or PLANTS. 



globe ? Murray's edition of the Linnean system contains, includ- 

 ing cryptogamia, only 10 ; 042 species. Willdenow, in his edition of 

 the Species Plantarum between the years 1797 and 1807, had 

 already described 17,457 phsenogamous species (from Monandria to 

 Polygamia dioecia). If we add 3000 cryptogamous species, we 

 obtain the number which Willdenow mentions, viz. 20,000 species. 

 More recent researches have shown how much this estimation of the 

 number of species described and contained in herbariums falls short 

 of the truth. Robert Brown counted above 37,000 phaenogamous 

 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 44,000 phaeuoga- 

 mous and cryptogamous plants. (Humboldt, de distributione geo- 

 graphica Plantarum, p. 23.) Decandolle found, in comparing Per- 

 soon's Enchiridium with his Universal System in 12 several families, 

 that the writings of botanists and European herbariums taken 

 together might be assumed to contain upwards of 56,000 species of 

 plants. (Essai elernentaire 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 

 25,000 phaenogamous plants cultivated, we shall easily perceive how 

 much Decanclolle's number falls short of the truth. Completely un- 

 acquainted 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 de la Sierra, and all the countries between 

 the Orinoco, the Rio Negro, the Amazons, and Puruz) of Africa, 

 Madagascar, Borneo, and Central and Eastern Asia the thought 

 rises involuntarily in the mind that we may not yet know the third, 

 or probably even the fifth part of the plants existing on the earth ! 

 Drege has collected 7092 species of phaenogamous plants in South 

 Africa alone. (See Meyer's pflanzen geographische Documente, s. 

 5 and 12.) He believes that the Flora of that district consists of 

 more than 11,000 phaenogamous species, while on a surface of equal 

 area (12,000 German, or 192,000 English square geographical miles) 

 von Koch has described in Germany or Switzerland 3300, and De- 



