[5]

Introduction, after speaking of Heterostyled Plants

They cannot be known with certainty merely by the different lengths of the ♂ & ♀ organs, [illeg] as larger number of individuals coexisting in about equal number, & within intermediate gradations are observed. If in addition If, however, Difference in the size of the pollen-grains & in the structure of the stigma is are observed in only a pair the 2 forms is a very impotent of plants they may be solely considered as Heterostyled. But the best evidence of all is the improved power of reciprocal fertilisation if when reciprocally visited. Cause of error, the growth of the pistil — 2d more variability ─ an incipient dioecious condition, with decreased length of the pistil in one form & decrease length of the stamen in the other; but this can generally be disturbed by a part of the pollen-grain by force.