Chap. XI. 



LEAVES AND SHOOTS. 



383 



J* 



heterophyllous varieties, in which the tree habitually bears leaves of various 

 forms; but it is probable that most heterophyllous trees have originated as 

 seedlings. There is a sub-variety of the weeping willow with leaves rolled 

 up into a spiral coil ; and Mr. Masters states that a tree of this kind 

 kept true in his garden for twenty-five years, and then threw out a single 

 upright shoot bearing flat leaves. 60 



I have often noticed single twigs and branches on beech and other trees 

 with their leaves fully expanded before those on the other branches had 

 opened; and as there was nothing in their exposure or character to 

 account for this difference, I presume that they had appeared as bud- 

 variations, like the early and late fruit-maturing varieties of the peach 

 and nectarine. 



Cryptogamic plants are liable to bud- variation, for fronds on the same 

 fern are often seen to display remarkable deviations of structure. Spores, 

 winch are of the nature of buds, taken from such abnormal fronds, repro- 

 duce, with remarkable fidelity, the same variety, after passing through the 

 sexual stage. 61 



With respect to colour, leaves often become by bud-variation zoned, 

 blotched, or spotted with white, yellow, and red ; and this occasionally 

 occurs even with plants in a state of nature. Yariegation, however, appears 

 still more frequently in plants produced from seed ; even the cotyledons 

 or seed-leaves being thus affected. 62 There have been endless disputes 

 whether variegation should be considered as a disease. In a future chapter 

 we shall see that it is much influenced, both in the case of seedlings and 

 of mature plants, by the nature of the soil. Plants which have become 

 variegated as seedlings, generally transmit their character by seed to a 

 large proportion of their progeny ; and Mr. Salter has given me a list of 

 eight genera in which this occurred. 63 Sir F. Pollock has given me 

 more precise information: he sowed seed from a variegated plant of 

 Ballota nigra which was found growing wild, and thirty per cent, of the 

 seedlings were variegated ; seed from these latter being sown, sixty per 

 cent, came up variegated. When branches become variegated by bud-varia- 

 tion, and the variety is attempted to be propagated by seed, the seedlings 

 are rarely variegated; Mr. Salter found this to be the case with plants 

 belonging to eleven genera, in which the greater number of the seedlings 

 proved to be green-leaved ; yet a few were slightly variegated, or were quite 

 white, but none were worth keeping. Variegated plants, whether originally 

 produced from seeds or buds, can generally be propagated by budding, 

 grafting, &c. ; but all are apt to revert by bud-variation to their ordinary 

 foliage. This tendency, however, differs much in the varieties of even the 

 same species ; for instance, the golden-striped variety of Euonymus Japonicus 

 " is very liable to run back to the green-leaved, while the silver-striped 





60 Br. M. T. Masters, * Eoyal Insti- 

 tution Lecture,' March 16, 1860. 



See Mr. W. K. Bridgman's curious 

 Paper in ' Annals and Mag. of Nat. Hist.,' 

 December, 1861; also Mr. J. Scott, 



• Bot. Soc. Edinburgh,' June 12, 1862. 



62 ' Journal of Horticulture,' 1861 , p. 

 336 ; Verlot, * Des Varietes,' p. 76. 



63 See also Verlot, 'Des Varie'tes,' 

 p. 74. 



