Mutations in Horticulture 621 



between the first culture and the first variation 

 of Crambe maritima. Other cases are on rec- 

 ord in which the variability exhibited itself 

 much sooner, perhaps within a few years after 

 the original discovery of the species. But such 

 instances seem, as a rule, to be subject to doubt 

 as to the concurrence of hybridization. So for 

 instance the Iris Lortetii, introduced in the year 

 1895 from the Lebanon, which produced a white 

 variety from its very first seeds. If by chance 

 the introduced plants were natural hybrids be- 

 tween the species and the white variety, this ap- 

 parent and rather improbable mutation would 

 find a very simple explanation. The length of 

 the period preceding the first signs of variability 

 is largely, of course, due to divergent methods 

 of culture. Such species as Erythrina, which 

 are perennial and only sown on a small scale, 

 should not be expected to show varieties very 

 soon. Annual sj^ecies, which are cultivated 

 yearly in thousands or even hundreds of thou- 

 sands of individuals, have a much better chance. 

 Perhaps the observed differences are largely 

 due to this cause. 



Monstrosities have, from time to time, given 

 rise to cultivated races. The cockscomb or 

 Celosia is one of the most notorious instances. 

 Cauliflowers, turnips and varieties of cabbages 

 are recorded by De Candolle to have arisen in 



