Thus Eschscholtzia is completely
self-sterile in the hot climate of Brazil, but is perfectly fertile
there with the pollen of any other individual. The offspring of
Brazilian plants became in England in a single generation partially
self-fertile, and still more so in the second generation. Conversely,
the offspring of English plants, after growing for two seasons in
Brazil, became in the first generation quite self-sterile. Again,
Abutilon darwinii, which is self-sterile in its native home of Brazil,
became moderately self-fertile in a single generation in an English
hothouse. Some other plants are self-sterile during the early part of
the year, and later in the season become self-fertile. Passiflora alata
lost its self-sterility when grafted on another species. With Reseda,
however, in which some individuals of the same parentage are
self-sterile and others are self-fertile, we are forced in our ignorance
to speak of the cause as due to spontaneous variability; but we should
remember that the progenitors of these plants, either on the male or
female side, may have been exposed to somewhat different conditions. The
power of the environment thus to affect so readily and in so peculiar a
manner the reproductive organs, is a fact which has many important
bearings; and I have therefore thought the foregoing details worth
giving. For instance, the sterility of many animals and plants under
changed conditions of life, such as confinement, evidently comes within
the same general principle of the sexual system being easily affected by
the environment.
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