16 



DE. E. E. GATES— CONTEIBUTION TO A 



(diameter about 3 cm.) with short style, so that the anthers surround the stigma and 

 self-pollination takes place in the bud. The many wild races of 0. biennis differ widely 

 in leaf-characters and yary somewhat in size of flower. The races of 0. muricata have 

 smaller flowers with usually shorter style than O. biennis. This is the only distinction 

 which can be drawn which will apply to all known races. Many narrow-leaved races 

 of O. muricata occur, but certain races have broad leaves as well as small flowers, so that 

 the latter character alone is retained as delimiting this group of races (see Gates, 1911 d, 



p. 580). 



Below are represented the lines of difference which may be drawn between these four 



species and their relatives and segregates : — 



1. Flowers large (length of petals 35-50 mm.). Style long and flowers open- 



polliuated (except in 0. brevistylis, 0. Simsiana, and certain other 



forms) . 



a. Buds smooth or bearing only sliort hairs, rosette-leaves usually having 



basal lobes 0. grandiflora races. 



b. Buds bearing also long, pointed hairs, which arise from papillae ... 0. Lamarckiana races. 



2. Flowers small (length of petals 15-35 mm.). Style short, causing self- 



pollination , . 0. biennis races. 



3. Flowers smaller (length of petals 9-15 mm.). Style short, flowers self- 



pollinated , . . . 0. muricata races. 



Before proceeding to an examination of their characters and behaviour let me outline 

 the history of some of these races and their present distriliution in. America. 



History of Races. — I have devoted considerable attention (Gates, 1911a and 1911^) 

 to the history of the introduction of Oenotheras from America into Europe, tracing the 

 records of the individual races since the first introduction in 1614, as far as possible 

 from the early names, plates, herbarium specimens, and descriptions. Some of the main 

 conclusions may be mentioned here in condensed form. The earliest Oenothera, of 

 which there is any record, was brought to Europe probably in 1614 and grown in the 

 Garden at Padua. In 1619 0. Bauhin grew this race from seeds obtained from Padua, 

 and the species is described in the Appendix to Bauhin's * Pinax,' page 520 (1623). 

 Bauhin's original specimen no longer exists, but the evidence from all sources, though 

 inconclusive, indicates that this first introduction, Avhicli Bauhin named Lysimaehia 

 lutea corniculata, was a type of O. biennis, now wild in Europe, and having 

 larger flowers than the American races of 0. biennis now known, but smaller than 

 O. Lamarckiana or O. grandiflora. Afterwards various independent introductions and 

 descriptions of Oenotheras were made from time to time, and some of the data regarding 

 their names, origin, and probable identity are given in the following table. In some 

 cases it seems impossible to be certain regarding the identity of the plant described or 

 illustrated. But in a few instances comparisons are made or other data provided which 

 make the determination at least very highly probable. Thus the figure and description 

 of LyshnacJda Americana by Columna leaves considerable doubt retrardini? its identitv, 



though the plant moy perhaps have come from the same source as Alpine's Hyoscyamus 



