44 HETEROSTYLED DIMORPHIC PLANTS. Chap. I. 



and he does not doubt that these had imperfectly ferti- 

 lised it. 



I tried a few experiments by reciprocally fertilising the 

 two forms in the same manner as before, but my plants 

 were unhealthy, so I will give, in a condensed form, the 

 results of Mr. Scott's experiments. For fuller particulars 

 with respect to this and the five following species, the paper 

 lately referred to may be consulted. In each case the fer- 

 tility of the two legitimate unions, taken together, is com- 

 pared with that of the two illegitimate unions together, 

 by the same two standards as before, namely, by the pro- 

 portional number of flowers which produced good capsules, 

 and by the average number of seeds per capsule. The fer- 

 tility of the legitimate unions is always taken at 100. 



By the first standard, the fertility of the two legitimate 

 unions of the auricula is to that of the two illegitimate 

 unions as 100 to 80; and by the second standard as 100 

 to 15. 



Primula Sikkimensis. 



According to Mr. Scott, the pistil of the long-styled 

 form is fully four times as long as that of the short-styled, 

 but their stigmas are nearly alike in shape and roughness. 

 The stamens do not differ so much in relative length as the 

 pistils. The pollen-grains differ in a marked manner in the 

 two forms ; " those of the long-styled plants i re sharply 

 triquetrous, smaller, and more transparent than those of 

 the short-styled, which are of a bluntly triangular form." 

 The fertility of the two legitimate unions to that of the two 

 illegitimate unions is by the first standard as 100 to 95, 

 and by the second standard as 100 to 31. 



Primula cortusoides. 



The pistil of the long-styled form is about thrice as long 

 as that of the short-styled, the stigma being double as long 

 and covered with much longer papillae. The pollen-grains 

 of the short-styled form are, as usual, " larger, less trans- 

 parent, and more bluntly triangular than those from the 

 long-styled plants." The fertility of the two legitimate 

 unions to that of the two illegitimate unions is by the first 



