No. 539] ORIGIN OF SPECIES IN NATURE 657 



eight lots of Chelidonium majus laciniatum, two of 

 which have double flowers, the seed being obtained 

 through the exchange lists of various botanic gardens. 

 These eight lots apparently represent five distinct forms. 

 The differences are not great and probably would re- 

 main unnoticed by the casual observer. After constant 

 association with them one can not fail to recognize the 

 differences, however slight. But though slight, the dif- 

 ferences are constant. They consist in the degree of 

 laciniation as well as in degree of hirsuteness. It might 

 be argued that these differences perhaps are due to dif- 

 ferences in external conditions or in the age of the plants 

 or in seasons, etc., just as the leaves produced by Acer 

 saccliarinum var. Wieri, in the latter part of the summer 

 at the extremities of the long, slender twigs, have a 

 lamina far more reduced than those formed earlier in 

 the year. Roze calls attention to the fact that in his cul- 

 tures of Chelidonium luciniatuu) the degree of lacinia- 

 tion of the leaves increased as the season advanced, 41 

 the petals undergoing a similar change. He also noted 

 that the degree of laciniation increased with the amount 

 of light received. 



While we have noted that the differences between the 

 varieties are most marked in the early part of the year, 

 the fact that our cultures were carried out under uni- 

 form conditions as to soil, light and water supply, and 

 that the various types are recognizable even in the late 

 summer, seems to indicate that these forms are entitled 

 to varietal rank. The specimen illustrated in Fig. 5 

 ought to set at rest all doubts upon this point. One 

 hardly would care to account for the extreme reduction 

 of leaf surface in this case on the basis of the influence 

 of fluctuating variability. This form, in all probability, 

 is identical with the Chelidonium majus foliis et flore 

 minutissinie laciniatis of the Hortus regius (1661), which 



