42 A MANUAL OF THE CONiEE&ZE. 



stretching southwards through the Mexican territory into Guatemala, 

 but at a higher elevation. Forests of Pine cover the mountain 

 slopes at from 9,000 to 12,000 feet of elevation, and lower down, 

 interspersed among the trees and shrubs of other orders, the 

 Cypress, the Juniper, and the Yew have each their representatives. 



Within the Tropics, in both hemispheres, Coniferous trees and 

 shrubs form but a minute fraction of the entire arborescent 

 vegetation; thet ropical species belonging to the Order are moreover 

 unimportant compared with those of extra tropical regions. One 

 species of Pine (Pinus occidentalis) occurs on the mountains of 

 Cuba and St. Domingo, and two or three Podocarps are found 

 within the West Indian region. In tropical South America, 

 Podocarps are the sole representatives of the Coniferse, but there 

 are some species of Ephedra, a genus of Gymnospermous plants, 

 closely allied to the Order, natives of the same region. Within 

 the equatorial zone of South America, there are large tracts 

 called Llenos, grassy plains entirely destitute of trees, and some- 

 times flooded by continuous rain. The Andean region is also 

 treeless along the Pacific coast, but on the eastern slopes of the 

 Peruvian and Bolivian Andes, vegetation is abundant, among which 

 the only Coniferous plants are Podocarps, but the allied Order 

 Gnetacese, is represented by several species of Ephedra. Tropical 

 Africa is almost destitute of Conifers : one species of Podocarp is 

 reported from the island of St. Thomas, off the coast of Western 

 Africa; one of Widdringtonia in Madagascar, and the curious 

 Welwitschia is indigenous to the Kalahari region. The Flora of 

 the East Indian Archipelago includes more coniferous species than 

 that of any other tropical region. Pinus Merlcusii occurs in Sumatra, 

 P. insularis in the Philippine Islands, Dammara alba in Borneo, 

 Java, Celebes, &c. ; Gnetum Qnemon is common throughout the 

 region, and there are besides, six or seven other species of Gnetum 

 of local occurrence. 



The distribution of the ConiferEe in the Southern Hemisphere 

 offers scarcely any analogy to their spread over the Northern regions, 

 which is no more than might be expected from the peculiar con- 

 figuration of the land south of the Tropic of Capricorn, its com- 

 paratively limited extent, and the separations of the principal portions 

 from each other by an immense expanse of ocean > The Southern 



