TORREYA 



February, 1918. 

 Vol. 18 No. 2. 



ADDITIONS TO THE FLORA OF WESTERN OREGON 



By J. C. Nelson 



The conditions of plant growth are so favorable in that part of Af^iv 

 Oregon lying west of the Cascade Mountains, and the establish-<»07'^^ 

 ment of introduced species is so easy, that it is becoming a serious ^a v/i. 

 task to keep pace with the increase. Not only are plants properly 

 belonging to the Californian flora which prevails south of the 

 Calapooias constantly extending their range to the northward, 

 together with a steady immigration of inland species down the 

 valley of the Columbia, but there is a constant influx of European 

 immigrants which become self-sown and locally established very 

 rapidly. It is therefore a matter of some regret to the local 

 collectors who so warmly welcomed the latest manual covering 

 this region (Piper and Beattie's Flora of the Northwest Coast) 

 that its authors did not take more positive ground in regard to 

 the inclusion of these immigrants. Their problem is one which . 

 confronts every botanist who undertakes to catalogue the flora 

 of any considerable extent of territory. Two opposite points of 

 view are possible. Either all introduced plants may be excluded, 

 or all may be included. In the latter case, the list will be need- 

 lessly swelled by waifs and ballast-plants that will not persist, 

 and are in no sense real members of the local flora; in the former, 

 by leaving out all plants of foreign origin, some of the most abun- 

 dant and characteristic species may be omitted and the value of 

 the book to the local student seriously impaired. To the lay- 

 man, the most easily intelligible purpose of any descriptive flora 

 is to render it possible for any student to identify by its aid any 

 plant which he may find growing spontaneously within its geo- 



[Xo. I, Vol. 18 of ToRREYA, Comprising pp. 1-20, was issued 13 February 1918.I 



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