76 MUTATIONS, VARIATIONS, AND RELATIONSHIPS OF THE OENOTHERAS. 



inherent in the constitution of the plant. Fortunately I have been able to test this. In 

 the case of Lobelia syphilitica I first found the plants in the shade of some rather thick 

 underbrush, in the month of September. This growth was cut down the following spring, 

 and the place opened to the full glare of the sun. This was done three years ago, yet, every 

 autumn since, the plants have either reappeared, or else left offspring which have inherited 

 their albino nature. This shows them not only constant in their peculiarities, but also that 

 these are bred in the plant and capable of inheritance. Epiphegus -virginiana and Prunella 

 vulgaris offer the same proofs. Nor has the influence of locality much or anything to do 

 with it, for a plant of the Lobi-lia syphilitica (with white flowers), which originally grew in a 

 swamp, was transplanted to a dry garden a mile or more away, yet came up and blossomed 

 white the next year. 



Let us now see what the experience gained in cultivation of white varieties can tell us. 

 Perhaps the Japanese have brought the art of eliminating color from plants to the greatest 

 perfection. Scores of species and genera have been by them variegated in the most peculiar 

 manner. But this is never constant in this country, but after a while always tends to 

 revert to the primitive color again. * * * 



As there seems to be no tendency to reversion in these natural albinos, they might per- 

 haps be made permanent varieties and be valuable on that account. No doubt this per- 

 manence is due to the change being sudden, leaving no trace of color by intermediate steps, 

 while in cultivated examples the white has generally been obtained by a gradual selection of 

 less and less darkly colored ones, and hence there would be a greater tendency to reversion 

 back through these steps again. 



From the foregoing it is clear that retrogressive white-flowered derivatives 

 were seen to arise from colored parental forms by saltations in which the color 

 of the flower behaved as a unit-character, and furthermore that the new color- 

 less forms were constant and were not affected by environmental conditions. 

 These ideas in fact underlie an important part of the mutation theory, and the 

 statements by Dr. Hollick constitute the unexpanded thesis of the saltatory 

 behavior of one set of characters. Not the least interesting part of the dis- 

 cussion is that which in effect recognizes the fact that many white-flowered 

 and white-leaved forms in cultivation represent the extremes of fluctuating 

 variations, and that when artificial selection lapses these forms gradually 

 return to a normal mean ; also that some species, such as Hepatica triloba, may 

 also have an extremely wide range of fluctuating variability as to the flower- 

 colors. 



A dim realization of the importance of sports and of the necessity for some 

 other hypothesis besides natural selection to account for the existence of all 

 living plants seemed to be widespread among botanists about the time De Vries 

 began the investigations which have led to his conclusions as to the influence 

 of mutations. An interesting forecast as to the matter was made by the late 

 Thomas Meehan (Meehan, 1882). He said: 



The conclusion I have been forced to is that the odd forms we often find in nature are not 

 necessarily hybrids, but are as likely, if not more likely, to be the outgrowth of some internal 

 law of form with which we are as yet unacquainted. That they do not often perpetuate 

 themselves is [not] remarkable when we remember that of thousands of seeds produced on 

 anyone tree but a small percentage ever gets a chance to form, and of those which do sprout, 



