Note 29 — Chapter XXIII · DIRECT AND DEFINITE ACTION OF THE EXTERNAL CONDITIONS OF LIFE.
Reading edition
Gärtner, ‘Bastarderz.,’ s. 606, has collected nearly all recorded facts. Andrew Knight (in ‘Transact. Hort. Soc.,’ vol. ii. p. 160) goes so far as to maintain that few varieties are absolutely permanent in character when propagated by buds or grafts.