312 



D?:SCRIPTIONS OF THE SHRUBS 



The species seen Avith chalky bark is generally the White Biucn — Betula 

 alba — of Europe, which grows to the height of 80 feet in its regular form. 

 There are a score of named varieties some of which are low trees and some 

 only shrubs, as European White Birch — Betula p^ndula (552), 



The four si)ecies always shrubby in growth are : Scrub or Dwarf Birch 

 (553) — Betula glaiidulosa,— 1 to 4 feet high with rounded small leaves, 

 \ to 1 inch long, and brown glandular warty twigs; Dwarf Birch (554) 



— Betula nana, — a low spreading 

 smooth shrub rarely 4 feet high 

 with small rounded notched leaves 

 broader than long ; Low or Swamp 



Fig. 554. — Dwarf Birch. 



Fig. 555. — Low Birch. 



Birch (555) — Betula pumila, — 2 to 15 feet high with longer and less 

 rounded leaves having dense brownish hairs below when young; and 

 Shrubby Birch (556) — Betula humilis, — 2 to feet high, with glandular 

 twigs and crenately-serrate smooth leaves ^ to 1| inches long. . [Seeds.] 



Alnus. The Alders are generally shrul)by plants growing alnindantly 

 along streams and in damp places. They have alternate simple straight- 

 veined notched deciduous leaves and dry rounded cones which remain on 

 the bushes throughout the year ; these cones are the best test of the 

 alders. Most have catkin flowers opening in early spring. The species 

 with fall catkins is usually a tree to 30 feet, Seaside Alder' (557) — Alnus 

 marftima, — which has shining foliage and yellow catkins in August to 

 September. 



