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Supplementary Notes on Acorus and Arabis 



Roland M. Harper 



In Torre YA for December, 1936, I discussed the question of 

 whether Acorus Calamus was native in the United States or not, 

 and expressed considerable skepticism, on account of the species 

 being obviously planted or escaped in many places, and being- 

 known also in Europe and Asia. That article brought me more 

 letters than anything else I ever wrote for a botanical magazine, 

 most of them giving information about additional localities for the 

 species in question, which I hope to incorporate in some future 

 publication. One of my correspondents also called my attention 

 to the embarrassing fact that Murray F. Buell had published a 

 short paper on the same subject in Rhodora for October, 1935, 

 which I had been wholly unaware of, on account of not getting 

 that magazine for several years past. Mr. Buell concluded that 

 Acorus is native in North America, at least near the middle of 

 the continent, "though the records .... have become much 

 blurred by human interference." 



Charles C. Deam, in his splendid Flora of Indiana, 1940 (map 

 on page 271, text on page 277, particularly under Spafhyema), 

 says that Acorus is widely distributed in that state, flowering and 

 fruiting throughout, but prefers sunny places, never associating 

 with Spathyema. This would seem to indicate that it was not com- 

 mon in prehistoric times, when most of the state was presumably 

 covered with forest. 



On a visit to New York in June, 1940, for the first time since 

 1932, I saw for the first time Milton Hopkins's monographic study 

 of Arabis in eastern and central North America, in Rhodora for 

 March, April and May, 1937. It seems to be as good a piece of 

 work as could be done with existing herbarium specimens ; but 

 some additional references to literature on my A. Georgiana would 

 have made the story more complete, and rendered superfluous his 

 comment on the poor condition of one of my specimens, collected 

 in midwinter. 



Mr. Hopkins dug up some old specimens of A. Georgiana that 

 I had not seen, collected long before my time, in Georgia and 

 Alabama, by Chapman, Boykin and Mohr, none of whom recog- 

 nized it as undescribed. (Dr. Mohr's specimen from Pratt's Ferry, 



