AMENTIFERiE. 187 



Var. ^, pubescens. 



B. pul)csccns, Wallr. Sclicd. Crit. p. 499. 



Sterile branches and sometimes the fertile ones, and often the leaves, 

 at least those on the sterile shoots, pubescent. 



In woods, thickets, &c. Common, and generally distributed. 



England, Scotland, Ireland. Tree or Shrub. Late Spring. 



Very similar to B. verrucosa, but usually not so tall a tree, often in 

 the Scotch Highlands a mere shrub or even bush not more than 5 or 

 6 feet high. The principal point of difference lies in the scales of the 

 female catkin, which have the 2 lateral lobes ascending, and all the 

 3 lobes oval. The leaves are generally more ovate than in B. verrucosa, 

 the buds oval-ovoid, the stipules shorter in proportion to their breadth, 

 and there is a tendency in the leaves and young shoots to be more or 

 less pubescent; the leaves are also on shorter stalks, and the twigs are 

 less frequently pendulous. 



Common Birch. 



Frencli, Bouleau inihescent. German, Weichhaarige Blrhe. 



This species is distinguislied by botanists from the preceding as less elegant, some- 

 times not more than a bush, with the leaves always more or less ovate, and the catkin- 

 scales ovate and rounded, instead of elongated and tapering. When full-grown, the 

 birch is subject to a cnrions morbid affection, which causes dense tufts of twigs to 

 grow out every here and there upon the branches, sometimes to the number of fifty 

 or more on a single tree. During the summer these tufts are concealed by the 

 foliage ; but in winter, when the tree is leafless, they show conspicuously, and look 

 like obsolete rooks' nests. In Scotland they are termed " witches' knots." That the 

 birch is one of the earHest inhabitants of our island is shown in a very interesting 

 manner, mentioned by Dr. Grindon of Manchester, who says that it is found exten- 

 sively in the peat-bogs near that city. When the peat is reraoved during the process 

 of drainage, immense quantities of fragments of branches and twigs are found 

 embedded in the lower strata, with the silvery bark still adhering, and as bright 

 as when it grew, though the age must be 1,500 or 2,000. Besides the fragments of 

 branches at Lindow, there are found great pieces of the main trunks. 



SPECIES II.— BET UL A NANA. Linn. 

 Plate MCCXCVIl. 

 Beich. Ic. El. Germ ct Helv. Vol. XII. Tab. 



Leaves very shortly stalked or subsessile, suborbicular, obtuse, 

 deeply crenate. Catkin-scales of the female catkin deepl}' 3-cleft, the 

 sinus between the lobes extending more than half-way down. Fruit 

 with a narrow margin, but without a distinct wing, suborbicular. 



BR 2 



