442 Bicknell: Ferns and flowering plants of Nantucket 



plants of the season, reddening the fields and plains and damp 

 sandy levels along the shores. 



Note. — Mrs. Owen's catalogue includes Ritmex salicifolins 

 Weinm. and Rwnex verticUlaUts L. It has been recently shown 

 by Professor Fernald (Rhodora lo : 17-20. 1908) that our coast- 

 wise dock formerly referred to R. salicifolins should properly bear 

 the name R, pallidns Bigel. This plant may well occur on Nan- 

 tucket, although I saw nothing of it. Neither was R. verticillatus 

 met with. 



Polygonum maritimum L. 



Somewhat locally common on the coast sands, flowering 

 through August and September, 



In damp sand it sometimes flowers abundantly when erect and 

 less than 10 cm. high ; vigorous plants on dry white sand spread 

 widely from a deep woody root, the prostrate branches becoming 

 6 dm, in length. 



Polygonum aviculare L. 



Under this name alone it is not possible to report the status of 

 Polygonum aviculare on Nantucket with the definiteness proper to 

 a local flora. The name has long been so loosely construed that 

 it fails to convey an unmistakable meaning, nor can it be under- 

 stood from its use what particular plant of a considerable group is 

 sought to be referred to. Some form of definition is necessary in 

 order to give definite expression to the name. The binomial 

 has here succumbed to the polynomial and we have one of those 

 cases where so-called breadth of treatment in the interpretation of 

 species has served to obscure the facts of nature rather than to 

 make them clear. 



The botanical history of the plant furnishes also an excellent 

 example of the futihty of multiplying varietal names. Many va- 

 rietal subdivisions have been proposed under the species, yet, not- 

 withstanding the authentic bases of a number of them, few or none 

 remain in current use. 



As I apprehend the problem, the species Polygoiitim aviculare, 

 as commonly accepted, embraces a group of organic units more or 

 less clearly outlined which it is very expedient that we should be 

 able to deal with under distinctive names. An understanding of 



