Betulacetz Betula. 4 1 5 



foliage of the wild forms is extremely variable in size and out- 

 line, and there are some very distinct varieties in cultivation, 

 such as B. a. laciniata, with deeply cut leaves, and B. a. 

 populifolia, the American variety, with large triangular acu- 

 minate leaves. This species has a very wide range through 

 Europe, Northern Asia, and North America. The only objec- 

 tion to the Birch is its short life. 



B. nana is a mountain species occurring in Scotland, and 

 having about the same general distribution as the last. There 

 are also several North American hardy species, but they are too 

 near in aspect to our indigenous species to be desirable except 

 in a general collection. Some of them, however, are of 

 larger stature and more valuable as timber trees. 



2. ALNUS. 



Trees and shrubs in which the fleshy scales of the persistent 

 cone-like female catkins become indurated and ligneous as they 

 approach maturity. Stamens 3 to 5. This genus has about 

 the same range in the northern hemisphere as the last, and 

 extends to South America. The ancient Latin name of the 

 genus. 



1. A. glutinoscv. Alder. This is the only native species. 

 It is usually a shrub or small tree, though it occasionally attains 

 a height of 50 to 70 feet, and it abounds in the vicinity of 

 rivers and brooks. The ordinary variety may be distinguished 

 by the black bark, glutinous branches, and young leaves, which 

 are of an orbicular or obovate form with a wavy serrulate 

 margin. The female catkins are borne in racemes, and persist 

 during the winter. The variety aurea has golden foliage, and 

 imperial! s, laciniata, asplenifolia and quercifolia, have more 

 or less lobed or cut foliage ; the first having elegant drooping 

 branches and fern-like leaves. This species occurs throughout 

 Europe, North Africa, and North Asia. 



2. A. cordifolia. A very distinct South European species, 

 having more the aspect of a Poplar, the leaves being nearly 

 or quite glabrous, and somewhat shining, ovate or oblong- 

 cordate in outline, with a serrate margin. It is a fast-growing 

 tree with light-coloured bark. 



A. incana and A. serrulata are North American species, of 

 no especial interest to horticulturists. 



