DISTRIBUTION OE THE MOEE PEOMINENT NATURAL OEDEKS. 265 



Plantarum' are represented in Mexico and Central America, the absent tribe being 

 the Araucariese. Podocarpus itself is spread all over the West Indies, and in 

 South America it ranges from Colombia to Brazil and Chili ; and (Ersted records a 

 narrow-leaved species as growing on the mountains of Costa Rica, but we have seen 

 no specimens from within our limits. On the other hand, the distribution of the 

 Araucariese is comparatively remote from our region, the nearest stations being in 

 Brazil and Chili. Of the Cupressinese there are three and five species respectively of 

 the widely spread northern genera Cupressus and Junvperus in Mexico, and one of them 

 has been collected in Guatemala. Of the small yet notable tribe Taxodieae there is one 

 celebrated Mexican species of the genus Taxodium, otherwise represented only in the 

 south-eastern States of North America by a closely allied species (or variety) and by an 

 imperfectly known species in Chili. Of the Taxese there is one Mexican species of the 

 generally dispersed northern genus Taxus. Of the remaining tribe, Abietinese, there 

 are three genera, namely Pinus, Abies, and Pseudotsuga, and about twenty-one species 

 in Mexico and Central America. The last-named genus is a monotype, ranging from 

 Oregon to New Mexico, and reappearing in the mountains of Moran and Real del 

 Monte; whether it exist in the intervening country is problematical. Abies religiosa 

 is an endemic Mexican representative of its genus, which belts the northern hemi- 

 sphere in temperate regions. Finally there is the genus Pinus, the most numerous in 

 species of the order, and constituting a prominent feature in the vegetation of Mexico 

 and some parts of Central America. Indeed the uppermost forests consist almost 

 entirely of species of Pinus, and those next below largely of species of Pinus and 

 Quereus intermixed. Pinus and Quercus have nearly the same wide range in the 

 northern hemisphere ; but Pinus is not known to extend so far south as New Guinea 

 in the eastern hemisphere, and Nicaragua is apparently its southern limit in America. 

 One species at least of Pinus is common in Cuba ; one is found in San Domingo, and 

 one in the Bahamas. Altogether the genus Pinus, as usually limited, comprises about 

 seventy species, two thirds at least of which are American ; and nowhere else are such 

 broad expanses of pine-forests. There are twelve species of Pinus in the Atlantic 

 States; fourteen in California and northward, and four or five in the intermediate 

 regions. The forms of Pinus in Mexico are numerous, and the species difficult of 

 delimitation, and many of them imperfectly known. There may be a score of species, 

 either more or less ; and three or four extend into north-western regions ; two as far 

 northward as Oregon and British Columbia. 



The distribution of pines within Mexico and Central America presents some singular 

 anomalies, independent apparently of climate ; but until the species are better defined 

 their full significance cannot be appreciated. As might be expected, their lower limits 

 vary in different districts, but not always from explainable causes. Grisebach states * 

 that no species has been found in Mexico below the level of 3000 feet. Humboldt 



* Vegetation der Erde, ii. p. 317. 



