38 HETEROSTYLED DIMORPHIC PLANTS CHAP. L 



longing to the same form ; whilst those which were 

 spontaneously self-fertilised no doubt generally received 

 their own pollen. In a future part of this volume some 

 observations will be given on the fertility of a red- 

 coloured variety of the primrose. 



PRIMULA SINENSIS. 



In the long-styled form the pistil is about twice as 

 long as that of the short-styled, and the stamens differ 

 in a corresponding, but reversed, manner. The stigma 

 is considerably more elongated and rougher than that 

 of the short-styled, which is smooth and almost 

 spherical, being somewhat depressed on the summit ; 

 but the stigma varies much in all its characters, the 

 result, probably, of cultivation. The pollen-grains of 

 the short-styled form, according to Hildebrand,* are 

 7 divisions of the micrometer in length and 5 in 

 breadth; whereas those of the long-styled are only 

 4 in length and 3 in breadth. The grains, there- 

 fore, of the short-styled are to those of the long- 

 styled in length as 100 to 57. Hildebrand also re- 

 marked, as I had done in the case of P. veris, that the 

 smaller grains from the long-styled are much more 

 transparent than the larger ones from the short-styled 

 form. We shall hereafter see that this cultivated 

 plant varies much in its dimorphic condition and is 

 often equal-styled. Some individuals may be said to 

 be sub-heterostyled ; thus in two white-flowered plants 

 the pistil projected above the stamens, but in one of them 



* After the appearance of my that I erred greatly about the 



paper this author published some size of the pollen-grains in the 



excellent observations on the two forms. I suppose that by 



present species (' Bot. Zeitung,' mistake I measured twice over 



Jan. 1, 18C4), and he shows pollen-grains from the same form. 



