MAST-BEARING FAMILY 



447 



| in. long, found in the Scottish Highlands, is probably a hybrid 

 between the preceding and the following. 



4. B. nana (Dwarf Birch). — A small shrub with short-stalked, 

 roundish, crenate, glabrous dark-green leaves, and catkins not more 

 than \ in. long. — Mountain bogs in the north ; rare. — Fl. May. 

 Perennial. 



2. Alnus (Alder). — Trees and shrubs ; flowers all in catkins; 



carpinus b£tulus (Common Hombeam\ 



stamens 3 — 5 ; fruiting catkin short, with woody, persistent scales. 

 (Name, the Classical Latin name of the tree.) 



1. A. rotundifolia (Common Alder). — The only British species, 

 a small tree with greyish-black bark; branches triangular when 

 young ; leaves shortly stalked, obovate, cuneate, blunt, wavy, 

 serrate, glutinous when young, green on both surfaces ; catkins 

 appearing before the leaves, and the woody scales of the fruiting 

 ones remaining long on the tree. — Swampy ground throughout 

 most of the temperate regions of the globe. — Fl. March, April. 

 Perennial. 



