THE OTTAWA NATURALIST 



VOL. XXVIII. FEBRUARY, 1915. No. 11. 



HYBRIDIZATION IN THE GENUS VIOLA. 



By M. O. Malte and J. M. Macoun. 



Certain sections of the genus Viola, as is well known, 

 are characterized by that wonderful biological peculiarity, 

 generally termed cleistogamy. The showy flowers of our 

 spring violets generally live but a short time. Although being 

 sexually perfect, i.e., having stamens and pistils normally de- 

 veloped, they generally wither down without producing any 

 seed and the propagation of the individuals and the maintenance 

 of the species are secured through the cleistogamous flowers. 

 These generally appear comparatively late in the season and 

 reach their fullest development after the showy spring flowers 

 have disappeared. As a rule, the cleistogamous flowers are 

 without petals or have them incompletely developed, for which 

 reason they are often in descriptive botany, termed apetalous. 

 The whole flower has the appearance of a half -grown bud arrested 

 in its development. It is often inconspicuous to the eye be- 

 cause of its lack of attractive colours, or even wholly invisible 

 to the casual observer because not rarely it reaches its full 

 development hidden among the decomposed or half-decom- 

 posed remnants of plants which cover the ground, or it even 

 flourishes beneath the surface of the soil. 



These cleistogamous flowers, however, play the most im- 

 portant part in the life history of the individual as well as of 

 the species. In spite of their seeming incompleteness, theY 

 produce, without being aided by outer agencies, all the seed 

 needed for the maintenance of the species. Their pistils are 

 automatically fertilized b}^ the pollen shed from their stamens, 

 the result being the production of an abundance of seed. 



This mode of seed production, so different from the ordinary 

 way, did not fail to attract the attention of botanists at least 

 as far back as the 18th century. It was thought to be 

 strange and inexplicable in times w;hen sexuality in plants 

 was still disputed and when the importance of sexual organs 

 as foundations for a scientific plant system was first being 

 discussed. 



