Sports or bud variations.—These curious departures from the normal form can only be mentioned incidentally in this place, as they pertain more to variation than to malformation.
The occasional production of shoots bearing leaves, flowers, or fruits of a different character from those found on the normal plant, is a fact of which gardeners have largely availed themselves in the cultivation of new varieties. The productions in question have been attributed to various causes, such as cross-breeding, grafting, budding, dissociation of hybrid characters, or reversion to some ancestral form, all of which explanations may be true in certain cases, but none of them supply the clue to the reason why one particular branch should be so affected, and the rest not; or why the same plant, at the same time, as often happens in Pelargoniums, should produce two, three, or more "sports" of a different character.
These bud variations may be perpetuated by grafts or by cuttings, sometimes even by seed. With reference to cuttings a curious circumstance has been observed, viz., that if taken from the lower part of the stem, near the root, the peculiarity is not transmitted, but the young plant reverts to the characters of the typical form (Carrière). This circumstance, however, is not of universal occurrence.
For further particulars on this interesting subject the reader is referred to Darwin's 'Variation of Animals and Plants,' i, p. 373, where numerous references are given, and wherein certain well-known and highly remarkable instances, such as the Cytisus Adami, the trifacial orange, &c., are discussed.
FOOTNOTES:
[366] 'Nature-printed Ferns,' 8vo edition, vol. ii, p. 197.
[367] 'Gard. Chron.,' 1845. p. 790.
[368] 'A New Arrangement of Phænog. Plants,' p. 36.
[369] 'Bull. Soc. Bot. France,' 1856, t. iii, p. 569.
[370] The reader will find an abstract of Mr. Darwin's views in his work on the 'Variation of Animals and Plants,' vol. ii, p. 181.