Deckmbee 7, 1900.] 



SCIENCE. 



871 



and Colorado, eastern and central Wyo- flora extends along the headwaters and 



ming, and western Dakotas, Nebraska and tributaries of Columbia Eiver into the 



Kansas. They have a flora of their own, Eockies of Idaho, Montana and British 



mostly consisting of xerophilous plants, but Columbia. 



in the valleys along the water courses are A flora made up of so many elements 



brought in besides the transcontinental flora must naturally be very varied and exceed- 



mentioned above, also a few of another ele- ingly interesting. A comparison may well 



ment, viz : be made with that of the Alleghanies on 



7. The Prairie Flora of the Mississippi one hand and that of the Cascade Moun- 

 Vallet. The species of the typical Alle- tains and Sierra Nevada on the other. If 

 ghanian flora found in the Eockies are so this is done we find that the flora of the 

 few that they may practically be disre- Eockies resemble more the latter than the 

 garded. In all cases they are also repre- former. 



eented in the Prairie flora. The bulk of the forest of the Eockies is 



8. The Flora of the Staked Plains, made up of Conifers. Most of these are 

 which extends into southeastern Colorado common to the region and mountains of the 

 and northeastern New Mexico. The Staked Pacific Coast, but none of the trees are 

 Plains, with their best development in found in the Alleghanies or around the 

 northwestern Texas, are but a southern ex- Great Lakes. The White Spruce, Picea 

 tension of the Great Plains, but contain Canadensis, has been reported from northern 

 numerous plants not found on the latter, so Montana and Alberta, but I think errone- 

 that its flora may well be treated separately, ously so. Probably P. Columbiana, which 



9. The SoNORAN Flora, the general flora resembles it in habit and the glabrous 

 of the table-lands of northern Mexico, Ari- branches, has been mistaken for it. P. Co- 

 zona and southern and western New Mexico, lumhiana is otherwise much more closely 



10. The Great Basin Flora of Nevada, related to P, Engelmannii. Two prostrate 

 Utah, southern Idaho and southeastern shrubby species of Juniperus, J. Sibirica 

 Oregon. This can almost be regarded as a Burgsd. and J. postrata Pers. range across 

 desert flora. It is also met with outside of the continent. Both are subarctic and sub- 

 the Great Basin, especially in many places alpine. Besides these none of the Eocky 

 in the Green Eiver valley of Wyoming, Mountain conifers are found in the East, 

 Utah and Colorado. although they are often represented there 



11. The Columbia Valley Flora. This by closely related species.* 



* List of the Rocky Mountain Conifers and their representatives in the East and on the Pacific Coast 



Eocky Mountains. East. Pacific Coast. 



Pinus flexiUsl 1 ( Pinus flexilis 



Pinus albieauUs J [ Pinus albicaulis 



-r.. .. , T.. „ , ( Pinus monticola 



Pinus monticola Pinus Sirobus 1 „. -r , , . 



(. Pmus Lambertina 



Pinus edulis , Pinus monophylla 



_. . ^ , f Pinus aristata 



Pinus ansiata k _. _ ,, 



( Pmus Balfouriana 



Pinus ponderosa } t^. . t,. -, 



_. , y Pinus resmosa Pmus ponderosa 



Pinus scopulorum J 



( Pinus Virqiniana "I „. „ 



■n. T,, T.. ,• . . Pimis Murrayana 



Pmus Murrayana < Pmvs dtvaricata !■ „. , f 



_. , . , Pmus contoria 



\. Pmus echmata ) 



