10 



FOREST TREES OF NORTH AMERICA. 



the Pacific region are mingled with pines, a juniper, an arbntus, and various other species peculiar to the Mexican 

 platemi. Extensive forests of a cypress of Mexican origin also characterize this mountain vegetation. The 

 bottoms of the canons are lined with a dense growth of cottonwood, hackberry, a noble sycamore, an ash, a 

 cherry, and other deciduous trees. The high foot-hills and mesas are covered with open groves of various oaks 

 peculiar to the Mexican-Pacific region, here reaching, within the United States at least, their greatest development. 



Such are some of the prominent forest features of Xorth America; a dense forest, largely composed, except 

 at the north, of a great variety of broad leaved species, and extendiug from the Atlantic sea-board in one nearly 

 unbroken sheet until checked by insufficient moisture from further western development the forest of the Atlantic 

 region ; a forest of conifers, o<;cupyiug the ranges of the great Cordilleran mountain system, unsurpassed in 

 density iu the humid climafe of the coast, open and stunted in the arid interior the forest of the Pacific region. 



A uiore detailed examination of the distribution of North American arborescent genera and species will serve 

 to illustrate the wealth of the forests of the Atlantic and the comparative poverty of those of the Pacific region. 

 It will show, too, more clearly how widely the forests of these two great regions differ in composition. 



DISTRIBUTION OF GENERA. 



The forests of North America contain arborescent representatives of 158 genera; 142 genera occur in the 

 Atlantic and 59 genera in the Pacific region. Of the Atlantic genera, 48 are not represented in the United States 

 outside the semi-tropical region of Flor-ida. 



The following table illustrates the distribution of these genera; the genera of semi-tropical Florida are 

 designated by a 



Magnolia 



Liriodendron . . 



Asimina 



Anona 



Capparis 



"Cauella 



^Clusia 



Gordonia 



Fremontia 



Tilia 



Byraenima 



Guaiacum 



Porliera 



Xanthoxylnm 



Ptelia 



Canotia 



*Simaruba 



Barsera 



Amyris 



Swietenla 



*Ximenia 



Hex 



Cyrilla 



Cliftoaia 



Euonymug 



*Myginda 



*8cha!fferia 



*Reyno8ia 



Condalia 



Rhamuus 



Ceanothas 



'Colubrina 



^genius 



Uognadia 



Sapindus 



Hypelate 



Acer 



Negundo 



Rhus 



Pistacia 



GreDera I Genera 

 represented represented 



by arbO' 



rescent 



species in 



the Atlantic 



region. 



V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 



V 

 V 

 V 

 V 

 V 

 V 



V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 



V 

 V 

 V 

 V 



V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 



bj; arbo- 

 rescent 

 speciea in 

 the Pacific 

 region. 



V 



V 



V 

 V 

 V 



V 

 V 

 V 



V 



Eysenhardtia . . 



Dalea 



Robinia 



Olneya 



j'Piscidia 



Cladrastis 



Sophora 



Gymnoclados.. 



Gleditschia 



Parkinsonia . . . 



Cercis 



Prosopis 



Leucsena 



Acacia 



Lysiloma 



Pithecolobium . 

 *Chrysobalanu8 , 



Primus 



Vauquelinia . . . 



Cercocarpus . . . 



Pyrus 



CrattBgus 



Heteromeles... 



Amelanchier ... 



Hamamelis 



Liquidambar .. 



Rliizophora 



"Conocarpus 



Laguncularia . . 

 "Calyptranthes . 

 "Eugenia . 



Cereus 



Cornus 



Nyssa 



Sambucus 



Viburnum 



"Exostemma 



Pinckneya .... 



"Genipa 



'Guettarda 



Genera 

 represented 

 by arbo- 

 rescent 

 species in 

 the Atlantic 

 region. 







V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 



V 

 V 



V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 



V 

 V 

 V 

 V 

 V 

 V 

 V 

 V 



Genera 



represented 



by arbo- 



leseent 



species in 



the Pacific 



region. 



V 

 V 

 V 

 V 



V 

 V 

 V 



V 

 V 

 V 

 V 

 V 

 V 



V 

 V 



V 



