THE FLOKA OF SOUTH MEXICO. 145 



South Mexico. 



For reasons already explained in the sketch of North-Mexican vegetation, we can give 

 no definite particulars of the area of South Mexico, except its geographical limits. It 

 lies between about 16° and 23° of latitude, and 87° and 107° of longitude, yet in its 

 widest part, about 20° lat., it extends through only eight degrees of longitude. It is 

 reckoned that three fifths of the whole of Mexico consists of an elevated tableland, 6000 

 to 8000 feet above the level of the sea, from which rise numerous lofty ridges and 

 peaks. The principal peaks or volcanoes are: — Colima, Jalisco, 12,750 feet*; Cofre 

 de Perote, Vera Cruz, 13,420 feet ; Orizaba, Vera Cruz, 17,879 feet; Popocatepetl, 

 Mexico, 17,784 feet; Sempoaltepec, Oaxaca, 13,100 feet; and San Cristobal, Chiapas, 

 6500 feet. This great mountain-chain is nearly severed in the Isthmus of Tehuantepec. 



South Mexico is by far the best explored of our botanical provinces, and parts of 

 it at least, especially the region of Orizaba, vie in richness and variety of vegetation 

 with the most favoured districts of Colombia. From the great differences in elevation 

 of the various States, and the diverse climatal conditions in operation, it is obvious that 

 only by a series of pictures could an adequate idea of the vegetation of the whole country 

 be conveyed. Thus Yucatan, from its lowness, has an almost wholly tropical, though 

 very scanty, vegetation ; and from its proximity to the West Indies there is an inter- 

 mixture of characteristic West-Indian types of vegetation ; whilst other States 

 exhibit every type of vegetation from tropical to alpine. Numerous sketches of the 

 vegetation of more or less restricted areas of South Mexico are scattered through 

 a variety of publications in various languages, references to the majority of which are 

 given in the Bibliography at the end of this work ; but few of them are sufficiently 

 exact, or complete enough, to be used here. The best and most comprehensive is by 

 Richard and Galeotti, the substance of which is given further on, under the head of 

 " Altitudinal Distribution of Orchids." 



Liebmann's description of the successive zones of vegetation from the coast at Vera 

 Cruz to the summit of the peak of Orizaba f is a most interesting and instructive sketch,, 

 and we here give an abridged and condensed translation of it. 



The most interesting mountain in North America is the volcano of Orizaba. It 

 is only thirty leagues from the coast, from which the ground rises immediately though 

 imperceptibly to its foot, giving it an appearance of even greater height than it 

 possesses. Its cone, crowned with eternal snow, is 17,000 feet high, and can be seen 

 from a distance of 100 miles ; it extends north and south in two huge flanks, each of 

 which averages about 9000 feet in height. On journeying from Vera Cruz westward 



* These and other altitudes are mostly taken from Stieler's Hand- Atlas. 



t "Vegetation des Piks von Orizaba," Botanische Zeitung, 1844, pp. 668, 684, 699, 717, 734, 750, 767,, 

 781, et 797. 



biol. CENTK.-AMEB., Bot. Vol. IV., August 1887. u 



