2 SUPPLEMENT TO THE PINETUM. 



observes that the true Spruces (Abies) approach nearest to that 

 of Pinus ; and that upon close inspection still more so, than at 

 a first glance. He says, "For instance, if the leaves that stand 

 singly are examined minutely, it will be seen that several of 

 them have their surface grown together, and consequently they 

 are in tufts, like the leaves of the true Pines ; and as a proof 

 that this is the case, it will be found that there is no upper sur- 

 face on the leaves of the Spruces, but that the leaves present 

 only the under-surface on both sides ; as will be seen on com- 

 paring them with the leaves of the true pines. The seam where 

 the leaves are joined may be distinctly seen, for it forms a line 

 in relief on both sides of the leaves of the common Spruce ; 

 which is never the case when such line is formed by the mid- 

 rib, because it is then either on the upper or under side. 

 Some spruces have two leaves grown together, others four ; the 

 sheaths at the base of the leaves are not observable, but appear 

 to have grown together in the footstalk." In addition. Profes- 

 sor Link points out the following differences between the leaves 

 of the true Spruces (Abies) and Silver Firs (Picea). The leaves 

 of the Silver Firs, he says, " do not grow together ; but are 

 single, and have the usual form of single leaves, the mid-rib 

 being only visible on the under side ; the upper one having a 

 furrow down the centre of the leaf, is flat, divided at the point, 

 and dark green, with two white stripes on the under side, one 

 on each side of the mid-rib, and arranged in two or more rows 

 along the shoots in a more or less lateral position." 



Section I. VEEA, or the true spruces; having needle- 

 shaped leaves, placed all round the shoots, and pendulous 

 cones ; composed of numerous persistent thin scales, and 

 seeds with a short stiff deciduous wing, and hard bony shell. 



Page S. 

 Abies alba nana, Loudon, the Dwarf White Spruce. 

 Syn. Picea alba nana. Link. 

 A dwarf bush, seldom growing more than 3 or 4 feet high, 

 but very dense, and with a very neat appearance. 



