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is required to prevent this mistake. Before one can with certainty name a 

 new moss from America he must look up all the species of that genus 

 from Europe and eastern Asia, as many species of mosses grow on these three 

 continents with little variation. 



To name again a plant that one knows to have been named before is an 

 unpardonable sin in these days, unless for some reason the first name belongs 

 to another organism. 



As an illustration of the repeated rechristening let us take the case 

 of Polytrickuin cofninune, so named by Linnaeus in 1753. In 1789 it was 

 named Polytrichiiin serratiivi by Schrank; in 1791 P. yuccaefoliiim by 

 Ehrhart, and in 1824, P . propinqiitim by Robert Brown. From the fact that 

 they all used the generic name Polytrichum one would certainly infer that 

 this multiplication of names w^as not due entirely to ignorance although it is 

 of course possible that each thought his plant a different species from that 

 already described. 



In such cases the first name published with a reasonable description, 

 would seem to be the one that should be universally adopted, and this is the 

 contention of a large school of American botanists headed by Dr. N. L. Brit- 

 ton of the New York Botanical Gardens, whose watchword is priority even 

 to the position of two names on the same page. Yet this is not as simple a 

 matter as it seems at first, for it not infrequently happens that the first name 

 given to a plant was published in some obscure pamphlet that no one except 

 a bibliophile ever heard of, while the name by which the plant has been com- 

 monly known for years was published a little later in a well known and 

 standard work. Of course this describes an extreme case and there may be 

 all gradations. 



An illustration of such a case is the moss commonly known as Pogona- 

 itwibrevicaitle which was named by Beauvois in his Prodromus in 1805. The 

 moss continued to pass by this name until 1894, a period of eighty-nine 

 years, when Mrs. Britton called attention to the fact that the same plant was 

 described as Polytrichum tenue by Menzies in the Transactions of the Lin- 

 naean Society for 1798. Of course the fact that it was named as a Poly- 

 trichum does not affect the case as we are now discussing the species names. 

 But in such cases the narne is written thus, Pogonatttin temie (Menz.) E. G. 

 Britton, which being interpreted means that the name tenue was first given 

 to the species by Menzies but that it was first published as a Pogonatimi by 

 Mrs. Britton. 



The inconvenience caused by changes of this sort have led many to favor 

 the Berlin rule formulated by a congress of botanists at Berlin some years 

 ago. According to this rule names in use for fifty years are not to be dis- 

 placed by the discovery of an older but previously little used name. Of 

 course this leaves room for a diffe-rence of opinion as to the proper name to 

 use and consequently to a lack of uniformity, the goal of the sticklers for ab- 

 solute unqualified priority; but the author thinks that a new race of human 

 beings will have to be developed before a uniform system of nomienclature, 

 with no chance for difference of opinion or usage, will be universally adopted. 



(To be continued.) 



