300 Part III. Chapter 3. 
The genera Agave and Dasylirion have their headquarters in Mexico. 
There are recognized 140 species of Agave native to that country, while some 
are found north in Texas, Arizona and California; several in the West Indies 
and a number south in Honduras and Guatemala. The following list‘) gives 
those occurring out of Mexico: 
Agave asperrima J., Texas. Agave Newberryi E., Arizona. 
»  aurea T. S. B., California. »  Palmeri E., Arizona. 
»  caribaea B., West Indies. » Parryi E., Arizona, Mexico. 
»  dasylirioides J. & Bouche, »  Pringlei E., California. 
uatemala. »  Sebastiana Gr., California. 
»  deserti E., California. »  Seemanniana J., Guatemala. 
» excelsa J., Honduras. »  Shawii E., California. 
»  geminiflora Ker-Gawl., Peru. »  sobria T. S. B., California. 
>» hexapetala Jacq., West Indies. »  spicata Cav., Cuba. 
» huachucensis B., Texas. » subinermis M. Roem., Brazil. 
» maculata Regel, Texas. » virginica L., North America. 
»  Margaritae T. S. B., California. »  Woallisii J., New Granada. 
»  Morrisii B., Jamaica. 
Besides these are found earth inhabiting Bromeliaceae, Sedum- and Zche- 
veria species, Mimosa, Cassia, Ephedra and a host of other plants, which 
had their origin and are peculiar to the Mexican plateau. 
While the yegetation of a desert type reigns supreme over the greater 
part of Mexico and although differing widely in the different phytogeographic 
regions, it may be said in general to belong to one and that a xerophytic 
type, there are other elements in the vegetation of the country mainly confined 
to the higher mountains and the lower elevations along the sea coasts that 
demand our attention. 
7. Non-Desert Floral Elements of Mexico and Central Ameri0#. 
Mangrove Formations of Tropics. The mangrove formation common also 
to the West Indian islands extends along the entire east coast of Mexico and 
perhaps, as far north, as Corpus Christi in Texas. On the West coast, it 
extends, as far north, as the Gulf of California above Mazatlan”). As an element 
found also in the West Indies, it represents one which has probably existed 
along the sea coasts of the Caribbean Sea and Pacific Ocean during all the 
vicissitudes to which those coasts have been exposed since the evolution of 
the higher groups of plants to which the mangrove are phytogenetically related. 
There has, however, been a gradual northward extension of the mangroV@ 
vegetation, so that its present area is more extended than its past. | 
ı) With abbreviated authors: J. = Jacobi, T. S.B.—= Brandegee, B.= Baker, E.= Engelmann 
and others. 
2) See colored map: Rhizophora Mangle. 
