304 PHYSIOGNOMY OP PLANTS. 



If, then, we would attempt to solve the question spoken of in the 

 early part of this dissertation, by giving in an approximate manner 

 the numerical limit (le nombre limite of French mathematicians), 

 which the whole phanerogam SB now existing on the surface of the 

 earth cannot be supposed to fall short of, we may, perhaps, find our 

 safest guide in a comparison of the numerical ratios (which, as we 

 have seen, may be assumed to exist between the different families of 

 plants) with the number of species contained in herbariums and 

 cultivated in our great botanic gardens. I have said that in 1820 

 the number of species contained in the herbariums of the Jardin 

 des Plantes at Paris was already estimated at 56,000. I do not per- 

 mit myself to conjecture the amount which the herbariums of Eng- 

 land may contain ; but the great Paris herbarium, which was formed 

 with much personal sacrifice by Benjamin Delessert, and given by 

 him for free and general use, was stated at his death to contain 

 86,000 species ; a number almost equal to that which, as late as 

 1835, was conjecturally assigned by Lindley as that of all the spe- 

 cies existing on the whole earth. (Lindley, Introduction to Botany, 

 2d edit. p. 504.) Few herbariums have been reckoned with care, 

 after a complete and strict separation, and withdrawal of all mere 

 varieties. Not a few plants contained in smaller collections are still 

 wanting in the greater herbariums which are supposed to be general 

 or complete. Dr. Klotzsch estimates the present entire number of 

 phsenogamous plants in the great Royal Herbarium at Schoneberg, 

 near Berlin, of which he is the curator, at 74,000 species. 



London's useful work, Hortus Britannicus, gives an approximate 

 view of all the species which are, or at no remote time have been, 

 cultivated in British gardens : the edition of 1832 enumerates, in- 

 cluding indigenous plants, exactly 26,660 phsenogamous species. 

 We must not confound with this large number of plants which have 

 grown or been cultivated at any time, and in any part of the whole 

 British Islands, the number of living plants which can be shown at 

 any single moment of time in any single botanic garden. In this 

 last-named respect, the Botanic Garden of Berlin has long been re- 

 garded as one of the richest in Europe. The fame of its extraor- 

 dinary riches rested formerly only on uncertain and approximate 

 estimations ; and, as my fellow-laborer and friend of many years' 



