With the plants which were
self-fertilised during the successive generations, this latter important
source of some diversity of constitution will have been wholly
eliminated; and the sexual elements produced by the same flower must
have been developed under as nearly the same conditions as it is
possible to conceive.
In Table 7/C the crossed plants are the offspring of a cross with a
fresh stock, or with a distinct variety; and they were put into
competition either with self-fertilised plants, or with intercrossed
plants of the same old stock. By the term fresh stock I mean a
non-related plant, the progenitors of which have been raised during some
generations in another garden, and have consequently been exposed to
somewhat different conditions. In the case of Nicotiana, Iberis, the red
variety of Primula, the common Pea, and perhaps Anagallis, the plants
which were crossed may be ranked as distinct varieties or sub-varieties
of the same species; but with Ipomoea, Mimulus, Dianthus, and Petunia,
the plants which were crossed differed exclusively in the tint of their
flowers; and as a large proportion of the plants raised from the same
lot of purchased seeds thus varied, the differences may be estimated as
merely individual. Having made these preliminary remarks, we will now
consider in detail the several cases given in Table 7/C, and they are
well worthy of full consideration.
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