Es ist der Umstand nicht zu übersehen, dass die cultivirten Gewächste meistens in grösserer Anzahl neben einander gezogen werden, wodurch für die wechselseitige Befruchtung zwischen den vorhandenen Varietäten und mit den Arten selbst die günstigste Gelegenheit geboten wird.
The circumstance cannot be overlooked that cultivated plants are mostly grown in larger numbers next to each other, which affords most favourable conditions for mutual fertilisation between existing varieties and with the species themselves.
circumstance = Umstand See p. 10, s. 13.
quantity = Anzahl See p. 3, s. 8.
mutual fertilisation = wechselseitige Befruchtung Both Bateson and Sherwood have “reciprocal fertilisation” but it seems unlikely that Mendel uses the expression in its technical sense here, as he does elsewhere in his paper. See previous sentence and p. 9, s. 5.
with the species themselves = mit den Arten selbst Bateson wrongly uses the singular “the species itself”. The meaning of this addition is a little mysterious. The most likely explanation is that “existing varieties” refers to the members of hybrid series within a species, whereas “species themselves” refers to the respective parental species that produced the hybrid in the first place. Alternatively, it may be that Mendel is distinguishing here between hybrids from varieties and species hybrids, but since he denies that there is really a difference between varieties and species (see p. 7, s. 1), this makes little sense. A final alternative is that he is speaking of cultivated varieties and species growing in the wild, but again, Mendel’s denial that there is an essential difference between the two makes this reading unlikely.
.