318 
Dr Yuie on the use of Larch Bark 
well illustrates the link in the affinity of this tribe, with that 
of the Ephedracese. In all these instances, the dentate sheaths 
originate from the same plane, at the base of the respective nodes. 
In Equisetum, these are most prominent on the fertile shoots, 
which they protect and cherish in the commencement of the sea- 
son; but, in the subsequent barren shoots, being less wanted, they 
shrink and wither. Even in Thuia and Cupressus, the verticil- 
lated dentate nodes scarcely merit the name of leaves, the young 
succulent shoots supplying their place, and even during winter 
influencing the motion of the sap, which in this tribe resists the 
utmost rigour of cold 
In both these tribes the sap circulates chiefly in the vessels of 
the external cylinder of the stem, which in Equisetum is hollow, 
the root only being solid. These vessels extending longitudinally 
throughout its whole length, are visible even to the naked eye, 
in a cross section of the stem "f*. 
On the use of the Larch Bark in tanning f Leather. 
There are four species of the genus Larix : (1.) Z. pendula of 
Salisbury, Meier e d'Amerique^foliis hreviorihus.^ strohilis parvis 
S2ibglobosis, Mich, scarcely known to our planters, although far 
more hardy than (2.) our well known common Larch, L. 
ppramidalis ; (3.) L. microcarpa^ totally unknown in Scotland, 
but figured by Lambert. (4.) L. cedrus^ or the Cedar Larch, 
so well distinguished by its perennial leaves, forming in winter 
the chief ornament of our lawns. 
It is generally admitted, that the Siberian Larch, described 
by Gmelin, is the same species with our Common Larch, the 
introduction and extensive cultivation of which we owe to the 
late Duke of Athol, who originally obtained several young 
plants from Switzerland, which were planted in the lawn of 
Dunkeld ; and here was manifested the first proof of the 
incalculable advantages of planting this species. Within a 
period of fifty-four years, some trees had attained nearly the 
height of a hundred feet, and, at five feet from the surface, a 
* Wahlenberg et Humboldt de Distribut. Plant. 
Casts of the stems of plants, evidently of this tribe, are frequently found in 
ouv coal formations. 
