^4 Mr. R. B. Hinds on Geographic Botany. 



volea, Spigeliacece, Stylidece, Tropceolea, Amaryllidea, Hmnodo- 

 racea, Iridece, Restiacea. 



As has been stated, a considerable number of the natural fami- 

 lies are represented in all the six divisions, and, caetens paribus, 

 those with the largest amount of species may be justly supposed 

 to be in this respect the most prominent. With increased num- 

 bers not only are the means of repetition multiplied, but there is 

 greater scope for variety of habit and predilection ; the former 

 displayed in the diversity of herbs, shrubs and trees, and the 

 latter in peculiarity of constitution. Those most distinguished 

 for a large amount* of species, as Cruciferce with 990, Myrtacece 

 715, Leguminosm 3875, UmbellifercB 1009, Cinchonacea 1631, 

 CaryophyllecB 759, have the most extensive range. It does not 

 appear that the habitat is influenced by the number of genera, as 

 might at first be supposed, since there are comparatively few in 

 Malvacece, CaryophyllecEj Leguminos(2 and GeraniacecB ; about the 

 average number in Cruciferce, but below it in Cinchonacece. Of 

 the hundred natural groups previously referred to, thirty-three 

 are distributed through all the divisions, whilst 



Europe has representatives of . . 53 



Asia 83 



Africa 76 



North America 81 



South America 83 



Australasia 53 



Confined to a single division . . 9 



The number of genera composing the families varies con- 

 siderably ; those of tropic or sub-tropic regions appear to have 

 more than others of temperate regions in proportion to the spe- 

 cies ; but the tropic families do not abound generally either in 

 genera or species. Leguminosce with 272 genera, CinchonacecB 

 215, Cruciferce 100, UmbellifercB 160, are among the largest. 

 Some consist only of one or two genera and scarcely more species ; 

 others with a large amount of species have but few genera, as 

 GeraniacecB with 490 species and only five genera ; LoranthacecB 

 330 species and four genera; OocalidecB 159 species and also four 

 genera. As instances to the contrary are Aurantiacece with forty- 

 four species and twelve genera; Olacinece seventeen species and 

 eight genera; Droseracece forty-five species and eight genera; 

 with BombacecBj Meliacecs, Magnoliacece, Flacourtianeae. Taken 

 collectively, the whole amount of natural families possesses an 

 average of upwards of eighteen genera each, or more correctly 



* The numbers stated are obtained from DeCandoUe's * Prodromus Regni 

 Vegetabilis.' 



