87^ 



SCIENCE. 



[N. S. Vol. XII. No. 310. 



Among the deciduous trees and shrubs, 

 the number of species common to the 

 Rockies and the East is much larger. Many 

 of these common species are boreal, but 

 some are truly transcontinental or nearly so. 



Of the SALlCACBiE about three-fifths of the Rocky 

 Mountain species are endemic or western. The rest 

 are nearly all boreal. The only ones that cannot 

 come under these categories, as far as I can remember, 

 are Salix Behbiana, S. Candida and S. cordata. The 

 eastern Populus deJtoides is represented in the Bookies 

 by a western variety. 



Of BETULACEiE, Betula papyrifera, B. gJandulosa, 

 Alnus AInoieiula and perhaps A. incana are found both 

 in the Rockies and in the East. The other four Rocky 

 Mountain species are western. 



Of FAGACEa;, Corylus rosirata is common to the 

 Rockies and the East. Besides by this species, the 

 family is represented in the region by a few endemic 

 low species of Quercus of the White Oak group. 



TJlmace^ is represented by three or four species of 

 Celtis, of which C- occidenialis is found in the East. 

 Ulmus Amen.nna is found here and there in the val- 

 leys of the Great Plains, but scarcely reaches the 

 Rockies. 



All woody species of HYDRANGiACEiE, Geosula- 

 biace^,Rosace«,Pomace.3j;, Drupace«, Papilion- 



ACK.*:, RUTACEiE, RHAMNACEiE, AOEEAOE^, CELAS- 



TEACB.S; and ANACHAEDlACEiE are endemic or west- 

 ern, except four species of Bibes, four of Bosa, Bubus 

 strigosus, Dasifora fruticosa, Sorbus sambucifolia, Biu- 

 nus Americana, P. Pennsylvanica, Amorpha fruticosa, 

 Bhanmus alnifoUa, Acer Negundo and Bhus glabra, 

 which are also found in the East. 



The two species of Vitace^ found in the Rookies, 

 viz., Viiis vulpina and Partenocissus quinquefolia ex- 

 tend to the Atlantic coast, and so also the three spe- 

 cies of ELa;GANACE^. 



Taken as a whole, scarcely 20 per cent, 

 of the woody plants of the Rockies are 

 found in the Alleghanies or around the 

 Great Lakes. Nearly all those common 

 to both regions are transcontinental or 

 boreal species. If on the contrary, the 

 woody flora of the Rocky Mountains were 

 compared with that of the mountains of 

 the Pacific Coast, one would find that at 

 least 50 per cent, of the former would be 

 represented in the northern Cascade Moun- 

 tains, which in British Columbia are more' 

 or less contiguous to the Rockies. 



It has been impossible for me to make a 

 detailed comparison of the general flora of 

 the Rockies with that of the East on one 

 hand and with that of the Pacific States on 

 the other. In my catalogue of the flora of 

 Montana and the Yellowstone Park, I 

 made such a comparison, and I think that 

 the conclusiou reached there with some 

 modification may serve for the whole Rocky 

 Mountain region. The catalogue contains 

 1,976 species and varieties. Of these 487 

 are found both east and west of the moun- 

 tains and 268 only east thereof, or in other 



Larix occidenialis 1 

 Larix Lyallii ) 

 Picea Parry ana ") 

 Pieea Engelmannii I 

 Picea Columbiana ) 

 PseudoUuga mucrunata 

 Abies grandis 1 

 Abies amabilis '. 

 Abies concolor f 

 Abies lasiocarpa ) 

 Thuja plicata 

 Jimiperus scopulorum 1 

 Juniperus Knighti J 

 Juniperus occidentnlis 1 

 Juniperus monosperma J 

 Juniperus prostrata 

 Juniperus Sibirica 

 Taxus brevifolia 



Larix laricina 



r Picea Canadensis 

 < Pieea rubra 

 (. Picea Mariana 

 [Tsuga Canadensis) 



Abies balsamea 



Thuja occidenialis 

 Juniperus Virginiana 



Juniperus prostrata 

 Juniperus Sibirica 

 Taxus Canadensis 



(Larix occidenialis 

 Larix Lyallii 



Picea Sitchensis 



Picea Engelmannii 



Picea Columbiana 

 Pseudoisuga mucronaia 

 r Abies grandis 

 J Abies amabilis 

 I Abies concolor 

 \^ Abies lasiocarpa, etc. 

 Thuja plicata 



Juniperus California 



( Juniperus occidenialis 

 ' \ Juniperus monosperma, etc. 

 Juniperus prostrata 

 Juniperus Sibirica 

 Taxus brevifolia 



