Nor did the short-styled P. hirsuta when
fertilised legitimately and illegitimately with the pollen of the two forms of
P. auricula. On the other hand, the short-styled P. auricula fertilised with
pollen from the long-styled P. hirsuta yielded capsules containing on an average
no less than 56 seeds; and the short-styled P. auricula by pollen of the short-
styled P. hirsuta yielded capsules containing on an average 42 seeds per
capsule. So that out of the eight possible unions between the two forms of these
two species, six were utterly barren, and two fairly fertile. We have seen also
the same sort of extraordinary irregularity in the results of my twenty
different crosses (Tables 2.14 to 2.18), between the two forms of the oxlip,
primrose, and cowslip. Mr. Scott remarks, with respect to the results of his
trials, that they are very surprising, as they show us that "the sexual forms of
a species manifest in their respective powers for conjunction with those of
another species, physiological peculiarities which might well entitle them, by
the criterion of fertility, to specific distinction."
Finally, although P. veris and vulgaris, when crossed legitimately, and
especially when their hybrid offspring are crossed in this manner with both
parent-species, were decidedly more fertile, than when crossed in an
illegitimate manner, and although the legitimate cross effected by Mr.
Pages:
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117