THE NEOTROPICAL REGIONS 279 



with those of temperate North America or Eurasia. The conif- 

 erous trees are absent, and deciduous trees are almost entirely 

 wanting. The characteristic deciduous trees of the boreal forests, 

 oaks, beeches, chestnuts, walnuts, poplars, birches, maples, etc., 

 are entirely unrepresented. A single willow (Salix Humboldtii), 

 which is common in the Amazon district, is about the only repre- 

 sentative of the catkin-bearing trees. It is true that in the warmer 

 parts of the United States, especially in southern Florida, which 

 almost touches the tropics, there are a good many trees and shrubs 

 which are evidently outposts of the tropical vegetation which 

 culminates in the great Amazonian forest. 



Our locusts and mesquit represent the great family of Legumi- 

 nosae, which probably has the greatest number of species in the 

 equatorial forest, and the sassafras and in the south Persea, a 

 tropical genus which includes the " avocado," represent the laurels 

 which have many tropical genera and species. Other cases might 

 be cited, but they are relatively unimportant. 



Rivalling the Leguminosae in number are the species of the 

 madder family (Rubiaceae). The most important of these, 

 Andean, however, rather than Amazonian, is the genus Cinchona, 

 the source of quinine. The Rubiaceae of temperate climates 

 are mostly insignificant herbs, like the bedstraws (Galium) and 

 the little bluets (Houstonia) of the Atlantic States. Both in the 

 Palaeotropics and Neotropics, a very large number of trees belong 

 to this family. 



The Leguminosae comprise an enormous assemblage of trees, 

 shrubs, and lianas, many of which have extremely abundant and 

 showy flowers at certain seasons. The sub-family Mimoseae 

 often have delicately cut graceful foliage, and flowers with clusters 

 of slender stamens, e. g., Inga, Pithecolobium; or like Cassia and 

 Bauhinia of the sub-family Caesalpineae, the flowers are open, 

 often suggesting an orchid. The pea-flowered type (Papilionaivae), 

 is less common, but still abundantly represented. 



The fig-family (Moraceae) includes a large number of species 

 other than Ficus. Among these are bread-fruits (Artocarpus 

 spp.), and other genera, one of the most not:il>lr being Cecropia, 

 a genus of trees, usually of comparatively small size, growing in 

 the riparian forest. They have hollow branches in which colonics 

 of ants are said to have their abode, and the long-stalked palmate 



