Wird angenommen, dass die Entwicklung der Hybriden nach dem für Pisum geltenden Gesetze erfolgte, so musste die Reihe bei jedem einzelnen Versuche sehr viele Formen umfassen, da die Gliederzahl bekanntlich mit der Anzahl der differirenden Merkmale nach den Potenzen von 3 zunimmt.
If it is assumed that the development of hybrids happened according to the law valid for Pisum, then the series in each individual trial had to comprise very many forms, since the number of members, as we know, grows with the number of differing traits as a power of three.
happened = erfolgte Mendel is switching to the past tense again, indicating that he is specifically talking about assumptions he is making about Gärtner’s actual experiments. Both Bateson and Sherwood use the present tense in their translations, and translate slightly misleadingly “follows”; cf. p. 35, s. 1.
law = Gesetze Mendel refers to the law formulated on p. 22, s. 7; see p. 18, s. 7 for further discussion.
trial = Versuch See p. 3, s. 6.
forms = Formen See p. 3, s. 8.
members = Glieder See p. 20, s. 12.
as we know = bekanntlich See p. 29, s. 7.
differing = differirend See p. 7, s. 3.
power of three = Potenzen von 3 Bateson has “in cubic ratio”, we follow Sherwood. The formula Mendel invokes here — 3n, with n being the number of “differing traits”, i.e. character pairs — is developed on p. 22, s. 9.