Gärtner hatte Gelegenheit, den Dianthus Armeria-deltoides bis in die 10. Generation zu verfolgen, da sich derselbe regelmässig im Garten von selbst fortpflanzte.
Gärtner had the opportunity to follow Dianthus Armeria-deltoides over 10 generations, because it regularly propagated itself in the garden.
itself = von selbst That is, spontaneously, without human interference. This makes it possible, of course, that the plant reproduced asexually.
Dianthus Armeria-deltoides On the genus Dianthus, see p. 37, s. 10. D. armeria is the grass pink, D. deltoides the maiden pink, both botanical names are still accepted today. For the statement Mendel is paraphrasing here, see Carl Friedrich Gärtner, Versuche und Beobachtungen über die Bastarderzeugung im Pflanzenreich (Stuttgart: Hering, 1849), p. 409. On D. Armeria-deltoides, see also p. 40, s. 7. On Gärtner, see p. 3, s. 4.