IDENTITY OF EVENING-PRIMROSES. 



Prepared by Anna Murray Vail. 



In view of the extent to which the evening-primroses are being used to 

 obtain experimental evidence upon questions of heredity at the present time, 

 it has been deemed important to make a systematic study of the group. To 

 this end seeds have been obtained from correspondents in various parts of 

 America and from European botanical gardens in which these plants appear 

 to be extensively cultivated. 



In the few years in which the cultures have been under way it has become 

 plainly apparent that a much larger number of species are native to America 

 than has been supposed hitherto. The series of pedigree-cultures made from 

 them, using carefully guarded seeds, shows that botanists have customarily 

 grouped many elementary species under the name of O. biennis. Furthermore, 

 as has been noted on page 8, none of these appear to coincide with the form 

 cultivated in Europe under this name. 



Several of these elementary species occur on Long Island, a number of them 

 collected by Mr. E. P. Bicknell deserving mention, and requiring special study 

 to determine their relationship to the common 0. biennis. 



Another group of closely related but apparently distinct elementary species 

 came from the west shore of Lake Champlain. There, in waste ground at the 

 roadsides about Plattsburg, fairly typical 0. biennis is to be found. A small- 

 flowered and very characteristic plant abounds on inland sand-dunes, in 

 sandy clearings along the Ausable River, and on the railroad embankments 

 near Bluff Point. In the Ausable River woods it grows associated with 0. 

 cruciata, and a supposed hybrid between the two was observed. Occasionally 

 a larger-flowered form on the edge of woods was observed and still another on 

 the gravelly shores of the lake. These types, with the exception of the hybrid 

 of which no mature seed was secured, were grown in the New York Botanical 

 Garden, where they reproduced in every particular the characters that distin- 

 guished them in the field. They will require more extended study for the 

 determination of their specific relationships. 



The more important facts concerning the anatomy and distribution of a 

 few forms have been obtained and descriptions of O. grandiflora, 0. simsiana, 

 O. oakesiana, 0. parviflora, and O. muricata are here presented. It is proposed 

 to reserve discussion of the large number of other distinct forms until their 

 life-history and hereditary qualities shall have been more definitely ascer- 

 tained. 



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