Comparison of the Old and New Species. 461 



In all these and other details the new species have the 

 flowers of Lamarckiana. But during the last two years 

 my mutants have overstepped even this limit; one hav- 

 ing appeared with hicnnis-^ow^vs and one with ;//z/n'ca/a- 

 flowers, not however in pure but in crossed strains. 



A curious form must be mentioned here, Oenothera 

 cruciata Nuttall which is described by some systematists 

 as a species, but regarded by others as a variety of O. 

 parviflora, from which it differs by its small linear petals 

 but in no other respect. It is therefore more closely allied 

 to O. parviflora than any two of my new species are to 

 one another. 



Lastly let us look at the fruits. The older species 

 resemble each other with the exception of O. parviflora, 

 in which the capsule is described as opening by eight 

 valves instead of four. The other alleged differences 

 such as cylindrical or conical form, greater or less degree 

 of hoariness, length and thickness, etc. are subject to a 

 very great extent to individual fluctuations and do not 

 seem to constitute differences of specific rank. 



On the other hand it is just in the characters of the 

 fruits and seeds that the new species differ most amongst 

 one another, as the table on page 453 and Figures 98 

 (group of seeds, p. 438) and 99-101 (fruits, pp. 446- 

 447) clearly show. 



We can sum up by saying that the known systematic 

 species of the subgenus Onagra differ from one another 

 in essentially the same way as do the forms which have 

 arisen from 0. Lamarckiana. The two groups are pre- 

 cisely analogous. The relation between the group of 

 Owflf^ra-species and O. biennis is the same as that between 

 the group of Lamarckiana-mwtdints and OenotJiera La- 

 marckiana itself. 



