330 BETULACEAE (BIRCH FAMILY) 



IHilt'irnrni, var. 'I'uckenu.) Alpine regions and cold bogs, Lab. to Sask., 8. to 

 11. N. E. and Minn. ((Jreenl.) 



^_ .H. Wings narrower than or rarely as broad as the body of the fruit, or want- 

 ing ; shrubs with dark scarcely pajtrry ba.rk, xubsessile or short-petioled 

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

 erect sessile or short-peduncled catkins. 



w Young bra nchlets pubescent with long soft hairs. 



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

 not glandular; young branches and lower face of young leaves mostly son- 

 downy; leaves obovate, orbicular, or renifonn, 1-3.5 cm. long, not resiniferoii*. 

 pale beneath, veinlets on both faces finely reticulated; fruiting catkins 0.7-3 cm. 

 long, 5-9 mm. thick. Bogs, Lab. and Nfd. to Out., s. to n. N. J., (_)., Ind., 111., 

 and Minn. (Eurasia.) 



Var. glandulifera Hegel. Young branchlets and leaves resiniferous or glandu- 

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



w Young branchlets glabrous or at most minutely puberulent, conspicuously 

 dotted with resinous wart-like gland*. 



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

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

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

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

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

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

 (Alaska; Asia.) 



5. ALNUS [Tourn.] Hill. ALDER 



Sterile catkins with 4 or 5 bractlets and 3 (rarely 0) flowers upon each short- 

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

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

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

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

 in fruit, wedge-obovate, truncate, or 3-5-lobed. Shrubs or small trees with 

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

 ancient Latin name. ) 



* Flowers developed with the leaves ; the sterile catkins from naked bud* fonm-d 



the preceding season; the fertile from scale-covered buds; fruit with a 

 conspicuous thin wing. 



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

 branches and peduncles sparingly puberulent or glabrate ; leaves round-oval, 

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

 or slightly pubescent on the principal veins beneath, irregularly serrulate or 

 liisci i ulate with very fine and sharp closely set teeth, the margins often puck- 

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

 long. (A. viri'ti's Man. ed. 6, in part, not DC.; A. Ahmbt-titlft Am. auth.. in 

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

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



'2. A. m6llis Fcrnald. (Dowvv (IRKKX A.) Shrub or small tree; >/nf/ 

 branflifs ami /tcil/nn-lcs permanently soft /// *-. tit; leaves pemiatientlij mr, r> </ 

 beneatli n-ith tli-nx<> soft Imirx, in maturity l.-~> 1 1 rut. hit/ ; mature fertile catkins 

 1.2-2 cm. long. (.1. riridis Man. ed. 0, in part, not DC.: .1. M in.lt nla Am. 

 aiith., in part, not K. Koch.) Damp thickets and exposed rocky banks, s. Nt'd. 

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

 Ordinarily distinct, but possibly an extreme variation of A. crix/m. 



* * Flnirt'i-s iltTt'lii/nil in i-iirlit'xt ftfiri/iii fn-fnre the learcs : the cutkitis all fmm 



naked bn<l* fnnmd tin i>r<*elin<j season ; fruit tcintiti** r u-ith a narrow 

 coriaceous manj in. 



