408 MB. C. DAUWIN ON TUE ILLEGITIMATE OFFSPRING 



pliism or trimorphism, when fertilized with their own pollen, are 

 in some degree dwarfed, and sometimes rendered sterile. None 

 of the nineteen plants in the first three classes attained complete 

 fertility ; one, however, made a near approach, yielding 96 per 

 cent, of the pro^^er number of seeds. From this high degree of 

 fertility we have many descending gradations, till we reach an ab- 

 solute zero, when the plants, though bearing many flowers, did 

 not produce, during successive years, a single seed or even seed- 

 capsule. Some of the most sterile plants did not yield a single 

 seed, even when legitimately fertilized by pollen from legitimate 

 plants. The first seven plants in Class I., which are by far the 

 most sterile, probably ought to form a distinct class from the 

 three following plants ; for there is reason to suspect that the 

 former are the product of the shorter stamens of the long-styled 

 form, whilst it is almost certain that the latter are descended from 

 the longer stamens of the same form ; but, owing to this doubt, 

 they are all arranged under the same class. The several classes 

 differ in their average degree of fertility ; and in the same class 

 there is a wide difference in the fertility of the several plants, 

 though descended from the same parents, sown at the same time, 

 and grown in the same soil. None of the plants in the first three 

 classes attained their full and proper stature ; the first seven 

 plants, which, as already stated, probably ought to form a distinct 

 class, are by far the most dwarfed, several of them never reaching 

 to half their proper height. These same plants did not flower at 

 so early an age, or so early in the season, as they ought to have 

 done. The anthers in many of their flowers, and in the flowers 

 of some other plants in the first five classes, were either conta- 

 bescent or included numerous small and shrivelled pollen-grains. 

 As the suspicion at one time occurred to me that the lessened fer- 

 tility of all the illegitimate plants might be due to the pollen 

 alone being affected, I may remark that this is certainly not the 

 case; for several of them, when fertilized by sound pollen from 

 legitimate plants, did not yield the full complement of seeds ; hence 

 it is certain that both the female and male reproductive organs 

 are affected. 



Turning now to the fourth, fifth, and sixth classes, and looking to 

 the right-hand column of the Table, we find nearly as many plants 

 with a percentage of seeds above the standard as beneath it. Hence, 

 at first sight, it appears probable that the number of seeds ordinarily 

 produced is much more variable than I have supposed, and, con- 



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