20, 21, 22. Canna warscewiczi.
Plants belonging to three generations were observed, and in all of three
the crossed were approximately equal to the self-fertilised; the average
height of the thirty-four crossed plants being to that of the same
number of self-fertilised plants as 100 to 101. Therefore the crossed
plants had no advantage over the self-fertilised; and it is probable
that the same explanation here holds good as in the case of Pisum
sativum; for the flowers of this Canna are perfectly self-fertile, and
were never seen to be visited by insects in the hothouse, so as to be
crossed by them. This plant, moreover, has been cultivated under glass
for several generations in pots, and therefore under nearly uniform
conditions. The capsules produced by the cross-fertilised flowers on the
above thirty-four crossed plants contained more seeds than did the
capsules produced by the self-fertilised flowers on the self-fertilised
plants, in the proportion of 100 to 85; so that in this respect crossing
was beneficial.
23. Primula sinensis.
The offspring of plants, some of which were legitimately and others
illegitimately fertilised with pollen from a distinct plant, were almost
exactly of the same height as the offspring of self-fertilised plants;
but the former with rare exceptions flowered before the latter. I have
shown in my paper on dimorphic plants that this species is commonly
raised in England from self-fertilised seed, and the plants from having
been cultivated in pots have been subjected to nearly uniform
conditions.
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