Studies on the Rocky Mountain flora — XXII 
Per AXEL RYDBERG 
ERIGERON 
Just as the writer resumed his work on Erigeron, Coulter and 
Nelson’s New Manual of Botany of the Central Rocky Mountains 
came out. From all evidences it is apparent that most of the 
work in connection with the new book has been done by Professor 
Aven Nelson, of the University of Wyoming. The work is a 
great improvement on the old Coulter’s Manual and it is perhaps 
the best manual that has been put out treating on the botany of 
the West. It has, however, many features to which the present 
writer is unwilling to subscribe. Dr. B. L. Robinson in his recent 
review* has pointed out the unevenness in the nomenclature, in 
that the Vienna Code has been followed in some cases, in other 
cases not. But this is easy for me to understand, for Professor 
Nelson has until lately followed the ‘“‘Rochester Code,” and it is 
not so easy to change the nomenclature of one’s thinking and 
writing and make it self-consistent. 
A few years ago, when Professor Nelson published his ‘““New 
Plants from Wyoming”’ in the Bulletin of the Torrey Botanical 
Club, he was about as “radical’’ as the present writer, and had 
about the same limitation of species. If we should judge from the 
New Manual, his conception of a species seems to have changed 
considerably, as seen from the number of specific names reduced 
to synonymy. Whether this change of attitude has slowly grown 
upon Professor Nelson or is due to influence from his collaborators, 
I can not tell. There is, however, one feature in this connection 
that seems to me somewhat unexplainable. Professor Cockerell 
in his reviewt of the book stated: 
“T have had the curiosity to count the number of species 
admitted as valid in the new manual, which were undescribed 
at the time of the publication of the first edition in 1885. They 
*Rhodora 12: 13-16. Ja 1910. 
7Science II. 31: 302. 1910. 
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