FLOWER- VARIATION 101 



nica. 1 "This plant," says Mr. G. A. Brennan, "presents, 

 as the result of thirteen years' cultivation, the curious 

 aspect of a monocotyledonous plant bearing in 

 bloom at the same time flowers of dimerous, trimerous, 

 tetramerous, pentamerous, hexamerous, and hepta- 

 merous types respectively, each flower bearing twice as 

 many stamens as sepals, petals, or carpels of the ovary. 

 The plant was set out in 1872, and received very rich 

 treatment, so that it gave forth blossoms measuring 

 two inches in diameter. In 1874 it began to depart 

 from the original trimerous type and to assume the tetra- 

 merous one, by developing another petal, and instead 

 of doing this at the expense of the pistil or stamens, it 

 added another sepal, another carpel with style, and two 

 stamens, thus making a typical tetramerous flower. 

 The plant has since then continued to differentiate in 

 a greater degree each succeeding year." In 1876 it 

 became pentamerous, in 1879 hexamerous, in 1882 

 dimerous, in 1886 heptamerous ; thus you perceive that 

 there has been no regular order in the course of 

 differentiation. At present, while the pentamerous 

 type is dominant in this plant, dimerous and hepta- 

 merous flowers are scarce. It seems that further 

 variation is forthcoming, for an octamerous ovary has 

 been detected in one flower. This fact is certainly 



1 G. A. Brennan : Variations of Tradescantia virginica. American 

 Naturalist, vol. xx. 1886, p. 55. 



