The. Cultural Evolution of Cyclamen latifolium. 



135 



March 18, 1897. 



The LORD LISTER, F.R.C.S., D.C.L., President, in the Chair. 



A List of the Presents received was laid on the table, and thanks 

 ordered for them. 



The following Papers were read : — ■ 



I. "The Cultural Evolution of Cyclamen latifolium (Sibth.)." By 

 W. T. Thiselton Dyer, C.M.G., CLE., F.R.S. 



II. " On the Conditions which render Absolute the Readings of the 

 Mercurial Thermometer." By S. A. Sworn. Communicated 

 by Professor Clifton, F.R.S. 



III. " Experiments on the Flame Spectrum of Carbon Monoxide." 

 By W. N. Hartley, F.R.S. , Royal College of Science, Dublin. 



<s The Cultural Evolution of Cyclamen latifolium (Sibth.)." By 

 W. T. Thiselton Dyer, C.M.G., CLE., F.R.S. Received 

 and read March 18, 1897. 



On the occasion of the discussion on " Variation in Plants and 

 Animals," which took place on February 25, 1895, it occurred to me 

 that it might be useful to give an illustration of the amount of 

 change which had been effected in a plant by continuous selection 

 under cultivation in a comparatively short time. I, therefore, placed 

 upon the table an example of the wild and of the cultivated form of 

 the garden "cineraria" (C. cruenta). 



The choice of this species was purely accidental. It was, however, 

 violently impugned. It was contended that the garden cineraria w r as 

 not the result of the development of a single species, but that it was 

 of multiple origin, and the result of the intercrossing of several. It 

 was further contended that its change from the wild form had not 

 been gradual, but by discontinuous steps or " sports." Neither con- 

 tention seemed to me well founded. But I admit that, owing to the 

 lapse of time since the so-called "improvement" of the cineraria 

 commenced, it is impossible to give formal proof that the process has 

 been what I described. Mr. Darwin met with the same difficulty. 

 He remarks : " We know hardly anything about the origin or history 



