TO WEE HISTORY OF CERTAIN COyiFERS. 



179 



If this be not a species, it is an exceedingly well-marked 

 variety, o^ving its peculiarities to climatal and geographical 

 influences, as pointed out by the late Mr. Murray. 



Fig. 10. 



A. Bract and scale of Abies co7icolor^ from the back ; B, scale with seed. 



In A, concolor (true) the young shoots are grey, hoary, yel- 

 lowish or olive-green. The buds (fig. 11) are rounded or dome- 

 shaped, pale-coloured, larger than in the chestnut-browa conoid or 

 pyramidal buds o^ A, grandis^ var. Zowiana, often very prominent ; 

 scales oblong obtuse. In addition to the terminal buds, others 

 appear at irregular intervals on the side shoots. The leaves are 

 in many ranks, thinly set, so that the shoot is exposed, more or 

 less upturned (fig. 9), all of about equal length, concolorous and 

 stomatiferous on both surfaces. As compared with the leaves of 

 A. graiidisy var. Loiviana (fig. 6), they are less regularly arranged, 

 in more numerous planes, they are given off from the branch at a 

 more acute angle, and are usually paler, narrower, and more 

 sharply pointed. 



The majority of the plants cultivated as A. concolor have the 

 leaves more nearly resembling those of -4. grandis^ var. Loiviana^ 

 and many of them may be included under my variety pallida. 

 The extreme forms may be considered as geographical varieties. 

 In any case, it is quite certain that great variation exists among 

 the seedlings in the same seed-bed. Supposing external circum- 

 stances to remain unchanged, much of this early variation may, 

 and probably will, disappear as the plants grow older; but it i» 

 easy to see how some of these forms may be better adapted for 

 certain conditions than others, and how they might in that case 

 be perpetuated. 



> 



