162 HETEROSTYLED TRIMORPHIC PLANTS. CHAP. IV. 



not one capsule was produced. So, again, the green, 

 large-grained pollen from the longest stamens of 

 the short-styled and mid-styled forms (in compart- 

 ments IV. and V.) is widely different. In both these 

 cases the difference in action is so plain that it cannot 

 be mistaken, but it can be corroborated. If we look 

 to Table 25 to the legitimate action of the shortest 

 stamens of the long- and mid-styled forms on the 

 short-styled form, we again see a similar but slighter 

 difference, the pollen of the shortest stamens of the 

 mid-styled form yielding a smaller average of seed 

 during the two years of 1862 and 1863 than that from 

 the shortest stamens of the long-styled form. Again, 

 if we look to Table 23, to the legitimate action on 

 the long-styled form of the green pollen of the two 

 sets of longest stamens, we shall find exactly the same 

 result, viz. that the pollen from the longest stamens of 

 the mid-styled form yielded during both years fewer 

 seeds than that from the longest stamens of the 

 short-styled form. Hence it is certain that the two 

 kinds of pollen produced by the mid-styled form are 

 less potent than the two similar kinds of pollen pro- 

 duced by the corresponding stamens of the other two 

 forms. 



In close connection with the lesser potency of the 

 two kinds of pollen of the mid-styled form is the fact 

 that, according to H. Miiller, the grains of both are 

 a little less in diameter than the corresponding grains 

 produced by the other two forms. Thus the grains 

 from the longest stamens of the mid-styled form are 

 9 to 10, whilst those from the corresponding stamens 

 of the short-styled form are 9 to 10 in diameter. 

 So, again, the grains from the shortest stamens of the 

 mid-styled are 6, whilst those from the corresponding 

 stamens of the long-styled are 6 to 6 in diameter. 



