90 TRANSACTIONS OK ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



Buds. — A has a decided covering of resin showing on the 

 adpressed scales, while B has little or no resin covering on the 

 scales, which are free at the tips and somewhat recurved with 

 fimbriated edges. 



Colour of the shoots, — B is decidedly warmer than A in colour. 

 The bark of the 2-year-old twigs of A is citron with distinct 

 greyish-green markings, while B has twigs russet coloured with 

 faint greyish-green markings. 



Leaves. — A has longer and slightly more glaucous needles 

 than B. The margins of the needles in both forms only show 

 fine serrations. Microscopic examination shows no distinct and 

 constant differences in cross-sections. 



It is of interest to note that, in 1811, G. Don of Forfar read a 

 paper on "Varieties of Pinus silvestris." 1 In this he stated that 

 he had, in 1810, observed that there were at least four varieties 

 of Scots r^ine. One of these (No. 2) he thought might be raised 

 to specific rank and named Pinus horizontalis . His first variety 

 was the one he considered of least value as a forest tree, seeming 

 " to be but short-lived, becoming soon stunted in its appearance, 

 and it is altogether a very inferior tree to varieties 2 or 3." The 

 characteristics he gave were that the branches formed a pyramidal 

 head, "the leaves being marginated," "dark or full green " in 

 colour and "but little glaucous" ; cones elongated and "taper- 

 ing to the point." The bark of the trunk was rugged. 



He stated that No. 2 (his Pinus horizontalis) was distinguished 

 from No. 1 by its horizontal branches, which tended to bend 

 downwards. "The leaves are broader than in variety 1 and 

 serrulated," lighter coloured and more glaucous. The bark 

 was less rugged, and the cones were thicker, smoother, and 

 not so pointed. He conjectured "that the fir woods which 

 formerly abounded in every part of Scotland, and the trees 

 of which arrived at large size, had been of this variety or 

 species." (Var. A above resembles this form in many ways.) 



His third variety was said to have lighter coloured leaves than 

 No. 2, "approaching a silvery tint." The branches formed a 

 head like variety 1. Its cones had "the appearance of being 

 beset with blunt prickles bent backwards." The leaves were 

 serrulated. "This variety," he said, "is more common than 

 No. 2, and it is also a good tree." He only found three or 

 four trees of the fourth variety, and he described these as 



1 Published in Memoirs of Caledonian Horticultural Society, vol. i., 1 814. 



