THE OTTAWA NATURALIST 



VOL. XXVIII MARCH, 1915. No. 12. 



HYBRIDIZATION IN THE GENUS VIOLA. 

 By M. 0. Malte and J. M. Macoun. 

 (Continued from page 150). 



As, however, the cleistogamous flowers are developed 

 comparatively late in the season, their failure to produce nor- 

 mal seed can be utilized as a means of determining the hybrid 

 nature of critical forms only by those students who have the 

 opportunity of studying the violets after the showy petaliferous 

 flowers have wholly or mostly disappeared, i.e., at a time when 

 the amateur botanist generally considers the violet season a 

 matter of the past. 



Early in the season, before the capsules of the cleistogamous 

 flowers are beginning to ripen, the hybrid nature of suspected 

 plants can be most satisfactorily ascertained through an exami- 

 nation of the pollen of their showy, petaliferous flowers, as 

 it is not only the sexual cells of the cleistogamous flowers which 

 are affected by hybridization, but also those of the petaliferous 

 ones. In other words, the whole sexual apparatus of a hybrid 

 plant, including both male and female organs, is conspicu- 

 ously deteriorated and incapable of normal functions. 



The stamens of a violet flower have, as is well known, 

 very short filaments, sometimes hardly -.visible to the naked eye. 

 Their anthers, on the other hand, a,re broad and composed of 

 two cells, separated by a rather conspicvious connective. The 

 latter carries on its top a peculiar appendage which is 

 generally brown or reddish brown. The anthers proper, that 

 is to say, the portion of the stamens below the appendages, 

 are placed close together and have the appearance of a cupola, 

 from the centre of which emerges the pistil. In their cells 

 they carry numerous pollen grains which, when normally devel- 

 oped, appear more or less triangular, quadrangular, or elliptic, 

 depending upon the species and also on from which side they 

 are viewed. 



