336 BETULACEAE (BIRCH FAMILY) 



papy racea, var. Tuckerm.) Alpine regions and cold bogs, Lab. to Sask., s, 

 n. N. E. and Minn. (Greenl.) 



- ->- Wings narrower than or rarely as broad as the body of the fruit, or wa 

 ing; shrubs with dark scarcely papery bark, subsessile or short-petio 

 thickish or coriaceous small leaves, and narrowly ovoid or cylindric mot 

 erect sessile or nhort-peduncled catkins. 



++ Young branchlets pubescent with long soft hairs. 



7. B. putnila L. (Low or SWAMP B.) Stems 0.5-3 m. high, erect or ascendi 

 not glandular; young branches and lower face of young leaves mostly M 

 downy ; leaves obovate, orbicular, or reniform, 1-3.5 cm. long, not resinife.ro 

 pale beneath, veinletson both faces finely reticulated; fruiting catkins 0.7-3 c 

 long, 5-9 mm. thick. Bogs, Lab. and Nfd. to Ont., s. to n. N. J., O., Ind., 1 

 and Minn. (Eurasia.) 



Var. glandulifera Regel. Young branchlets and leaves resiniferous or glam 

 lar-dotted. Ont. and Mich, to Minn, and Sask. 



** ft- Young branchlets glabrous or at most minutely puberulent, conspicuoii 

 dotted with resinous wart-like glands. 



8. B. glandulbsa Michx. (DWARF B.) Stems erect or depressed, 0.3-2 

 high, or when alpine procumbent; leaves wedge-obovate, 0.5-3 cm. long, gr 

 and glabrous both sides, slightly reticulated ; fruiting catkins 0.5-2.5 cm. lo 

 3-7 mm. thick. Arctic barrens, s. to- mts. of N. B., Me., and N. H. ; 

 Superior, Minn., etc. (Asia.) Var. ROTUNDIFOLIA (Spach) Regel. V 

 dwarf ; leaves orbicular or reniform. Arctic regions to mts. of Me. and N. 

 (Alaska ; Asia. ) 



5. ALWUS [Tourn.] Hill. ALDER 



Sterile catkins with 4 or 5 bractlets and 3 (rarely 6) flowers upon each sh( 

 stalked shield-shaped scale; each flower usually with a 3-5-parted calyx < 

 as many stamens ; filaments short and simple ; anthers 2-celled. Fertile catk 

 ovoid or ellipsoid ; the fleshy scales each subtending 2 flowers and a group 

 4 little scalelets adherent to the scales or bracts of the catkin, which are wo< 

 in fruit, wedge-obovate, truncate, or 3-6-lobed. Shrubs or small trees w 

 few-scaled leaf-buds and solitary or often racemose-clustered catkins. ('J 

 ancient Latin name.) 



* Flowers developed with the leaves ; the sterile catkins from naked buds forr 



the preceding season; the fertile from scale-covered buds; fruit witi 

 conspicuous thin wing. 



1. A. crispa (Ait.) Pursh. (GREEN or MOUNTAIN A.) Shrub with yoi 

 branches and peduncles sparingly puberulent or glabrate ; leaves round-o' 

 ovate or slightly heart-shaped, in maturity 3-6 cm. long, glutinous and smoi 

 or slightly pubescent on the principal veins beneath, irregularly serrulate 

 biserrulate with very fine and sharp closely set teeth, the margins often pu 

 ered ; fertile catkins slender-stalked, loosely racemose, in maturity 1-1.5 < 

 long. (A. viridis Man. ed. 6, in part, not DC. ; A. Alnobetula Am. auth. 

 part, not K. Koch.) Cool shores and mts., Lab. to N. B. ; Mt. Katahdin, M 

 Mt. Washington, N. H.; Whiteface Mt., N. Y. ; and on the mts. to N. C. 



2. A. m611is Fernald. (Dowxr GREEN A.) Shrub or small tree; t/oi 

 branches and peduncles permanently soft-pubescent; leaves permanently cove 

 beneath with dense soft hairs, in maturity 4.5-1 1 cm. long ; mature fertile catk 

 1.2-2 cm. long. (A: viridis Man. ed. 6, in part, not DC. ; A. Alnobetula A 

 auth., in part, not K. Koch. ) Damp thickets and exposed rocky banks, s. N 

 to L. Winnipeg, s. to s. Me. and N. H., w. Mass., N. Y., and L. Superior 

 Ordinarily distinct, but possibly an extreme variation of A. crispa. 



* * Flowers developed in earliest spring before the leaves ; the catkins all fr 



naked buds formed the preceding season; fruit wingless or with a nun 

 coriaceous margin. 



