242 AMENTACE.E. [Alnus. 



ORD. 70. AMENTACE^i. Juss. Amentaceous Family. 



Flowers dioecious, monceciojs, or rarely perfect. Barren 

 flowers capitate, or amentaceous, subtended with a scale or 

 scale-like perianth. Stamens inserted upon the scale, almost 

 always monadelphous ; anthers 2-celled. Fertile flowers fas- 

 cicled, solitary or in close catkins, subtended by a scale. Ovary 

 free, simple or rarely compound. Stigmas several. Fruits as 

 many as there are ovules, bony or membranaceous. Albumen 

 none or thin. Embryo straight or curved, plane ; radicle gene- 

 rally superior. Trees or shrubs, with mostly deciduous leaves, 

 the younger ones with two stipules at the base. 



I. Betulinece. Richard. 



Fruit indehiscent, membranous, 2-celled, with solitary ovules, 

 Seeds pedulous, naked. Trees or shrubs, with leaves having 

 their venae primaries running straight from the midrib to the 

 margin. 



1. BETULA. Linn. Birch. 



Barren fl. in a cylindrical catkin^ its scales 3-flowered. Pe~ 

 rianth none. Stamens 10 12. Fertile fl. Scale of the 

 catkin imperfectly 3-lobed, 3-flowered. Perianth none. 

 Styles two. Germen compressed, with two cells, one of 

 which is abortive. Nuts compressed, with a membranaceous 

 margin, 1 -seeded. Name, derived from betu, the Celtic name 

 for the birch. Moncecia. Polyandria. 



1. B. alba, Linn. Common Birch. Leaves ovato-deltoid, 

 acute, doubly serrated, glabrous. JBr. FL 1. p. 409. E. FL v. 

 iv. p. 153. E. Bot. t. 2198. 



Woods, especially in heathy soil in mountainous countries. FL 

 April, May. T? . The Weeping Birch, or Pearl Birch, although con- 

 sidered by some authors a distinct species, appears to be only a variety 

 of this, and may be readily distinguished in its young state by its pearly 

 or warty shoots, and when it acquires a considerable age by its pendu- 

 lous branches. The birch is one of the most hardy of trees. The 

 wood, which is tough and white, is employed for various purposes. 

 Much of it, and also the wood of the Alder, is burned into charcoal for 

 the manufacture of gunpowder and other purposes, and brooms are 

 made of its tops. The oil obtained from the " white rind" is said to 

 be used in tanning the well-known Russian leather. A wine is made 

 of its sap in Scotland. 



2. ALNUS. Tourn. Alder. 



Flowers collected into imbricated catkins. Barren fl. Scale of 



