22 A HANUAl OF THE CONIFER*. 



The deep glossy green of the leaves of Abies bradeata renders that 

 remarkable tree not less distinct and imposing than does its tall spiry 

 habit of growth. The pleasing glaucous hue of the Deodar Cedar is 

 almost unique, and the rich deep colour of Libocedrus deeurrens is 

 scarcely less so ; Pinus insignis is distinguished among all Pines by its 

 cheerful grass-green foliage, which affords a striking contrast to the dull 

 grey hues of many of its congeners; the difference in colour between 

 Abies nobilis and A. Nordmanniana is not less marked. The foliage of 

 Cryptomeria elegans changes in winter to a deep bronzy green tinged 

 with crimson, which makes this plant particularly ornamental at that 

 season, and a similar change takes place in Retinosjoora (TJmia) 

 ericoides, which becomes violet purple* The common Arbor Vitas 

 is brownish green, while varieties of the Chinese species have their 

 foliage of a rich golden-yellow during the growing season. Many of 

 the Junipers have a bluish glaucous tinge peculiar to them, and others 

 are quite grey. 



Besides the difference in tints above sketched, the foliage of Coni- 

 ferous plants is subject to two changes in colour, viz., variegation and 

 GLAUCBSCENCB, the causes - of which have not yet been clearly made 

 out. Variegation shows itself in the young growth of the plants, 

 which, instead of appearing in the shade of green natural to the species, 

 takes some shade of yellow that varies in the different kinds from a 

 deep golden hue to a creamy white. In some cases the whole of the 

 newly formed branchlets with their foliage is produced coloured, t As 

 the season advances, the tint gradually changes, first by becoming 

 deeper, then taking a perceptible shade of green, and finally in the 

 course of the second season, assuming the green natural to the species, 

 but not till a new coloured growth is formed. This kind of variega- 

 tion is observed to be tolerably constant in whatever description of 

 soil the plant is growing, but the intensity of the colouring is slightly 

 different in different soils, being most developed in clayey loams. In 

 other cases the tips of a portion of the branches only appear coloured, 

 the extent of the variegation ranging in different and in the same 

 species from a mere ' spot to a considerable portion of the branch. 

 It is only in this form that a white variegation appears. Plants 

 variegated in the manner first described, continue- to produce coloured 

 foliage year after year without manifesting any special signs of debility 

 or decay; but their rate of growth is always slower than that of the 

 normal forms. Plants partially variegated often show signs of disease 

 in the coloured parts, which turn brown and die, in some cases 



* The foliage of all or nearly all the Oonifera of temperate climates changes colour 

 in -winter more or less. This is due to the low temperature of that season, which causes 

 a peculiar transformation of the blue green constituent of chlorophyl. A higher temper 

 rature restores the normal condition. — Sach's Lehrbuch, p. 705. 



t As in Eeliiwspora obtusa aurea, R. plumosa aurca, Thuia aurea, Tttxus baccata aurea, 

 Junipcrus chinensis aurea, Thuia elegantwsima, &c. 



