668 BETULACEA. 
Scotch or Wych Elm, and others, is largely employed as timber, which is 
valuable not only for its toughness, but because it is not readily acted upon 
by water. The inner bark of U. fulva, the Slippery Elm or Red Elm, a 
native of the United States, where it is official in the Pharmacopeeia, is 
much used as a demuleent for both external and internal use. When 
ground it is said to form an excellent emollient poultice, like that of Lin- 
seed meal, It is also stated to have the property of preserving fatty sub- 
stances from rancidity, when these are melted and kept in contact with it 
for some time. 
Cohort 5. Amentales.—Flowers unisexual, in ordinary amenta 
or amentaceous heads. Calyx absent, or present and green, 
or represented by 1 or more bristles, bracts, bracteoles, or 
scales. Ovary superior, 1—2-celled. Seeds nearly always 
exalbuminous. Trees or shrubs. Leaves alternate, simple, 
and usually with deciduous or persistent stipules; or in 
Casuarinacez there are no evident leaves. 
Order 1. Brtunacrem, the Birch Order.—Character.— 
Trees or shrubs. Leaves simple, alternate, with deciduous 
stipules. Flowers small, unisexual, moncecious, amentaceous, 
with no true calyx, but in its place small scaly bracts, which in 
some cases are arranged in a whorled manner. Male flowers 
with 2 or 3 stamens opposite the bracts. Female flowers with a 
2-celled vvary, and 1 pendulous anatropous ovule in each cell. 
Fruit dry, thin, indehiscent, often winged, 1—2-celled, 1-seeded, 
without a cupule. Seed pendulous, exalbuminous; embryo 
straight ; radicle superior. Bentham and Hooker include this 
order in Cupuliferex as the tribe Betulex. 
Distribution and Numbers.—Vhey are principally natives of 
the colder regions in the northern hemisphere. Illustrative 
Genera :-—Betula, Linn.; Alnus, Tourn. These are the only 
genera; there are about 70 species. 
Properties and Uses.—They are valuable for their timber, 
and for their astringent, tonic, and febrifugal barks. 
Alnus.—A. glutinosa, the common Alder.—Its wood is valuable for the 
piles of bridges, and in other cases where entire submersion in water or 
damp earth is required. Its bark is astringent, and has been used in 
medicine, and for tanning and dyeing. The leaves and catkins have simi- 
lar properties. The wood is also employed for making charcoal, which is 
much valued for the manufacture of gunpowder. The bark of A. incana 
is used in Kamtschatka for making a kind of bread. 
Betula.—B. alba, the common Birch, yields the timber known as Norway 
sirch. ‘The wood is also used for making charcoal. From the bark, root- 
lets, and twigs of this species the oil known as Oleum Rusci or Birch Tar 
Oil, which gives the peculiar odour to Russia leather, is obtained. It has 
also a high reputation in Russia, Poland, &c., in certain skin diseases, more 
especially eczema. The sap contains in the spring a good deal of sugar, 
hence it is then used in the preparation of a kind of wine ; this is com- 
monly known as Birch wine, and is employed in domestic practice for 
those afflicted with stone or gravel.—B. nigra, the Black Birch of North 
America, is also valuable for its timber. Its sap, like that of B. alba and B. 
lenta, y ields sugar of good quality, and wine may be also prepared from it.— 
B. papyracea has a thick tough bark, which is used by the Indians in North 
