4G0 BKTULACEvE. (iJIRCIl FAMILY.) 



the oblong catkin tomentosc; the hnu'ts with oblong-linear nearly equal lobes; 

 fruit broadly winged. (15. rul)ra, Miilix. f.) — Low river-banks, E. Massachu- 

 setts to Illinois and southward. — A rather large tree, with light-colored wood, 

 and somewhat Alder-like leaves. 

 * # * * Shrubs, ivith brownish bark, loinnhd or ivKh/p-shnped crenrite and niost/i/ 



small leiires of tluckish or coriaanns texture, and obUnuj or ci/lindrical ijlahrons 



and mostly erect catkins, on short judiineles. 



6. B. ptimila, L. (Low Biucii.) Steins (2° -8° high) erect or ascend- 

 ing, ?io/ y/((Hrf((/ar; young branches and lower face of young leaves mostly so/?- 

 domui ; leaves obovate, roundish, or orbicular (6" - 1 6" long), pale beneath, veinUts 

 on bo(h faces finel ij reticulated ; wing of the fruit mostly narrower than the body. — 

 Bogs, Conn. (Canaan, W. H. Le(ifietl) to N. Jersey and northward. — Leaves in 

 one form resiniferous or glandular-dotted, usually not at all .so. — B. Grayii, 

 Kegel, recently characterized on specimens of a shrub introduced from ('entral 

 Ohio into the Cambridge Botanic Garden, since lost, appears to be only a marked 

 variety or luxnriant form of the present species, with shoots and young leaves 

 beneath more tomentosc, and wings of fruit (which are as wide as body in one 

 Michigan specimen of B. pumila) here alniosl twice us wide! 



7. B. glandulosa, Michx. (1)\v.\kf Birch.) Stems erect or mostly 

 spreading (l°-4° high), or when alpine procumbent; brawhlels e/htbrous, conspic- 

 uously dolled with resinous wart-like (/lands ; leaves roundish wcdge-obovate or 

 sometimes orbicular (6" -9" long), green both sides, less reticulated; fruiting 

 catkins mostly shorter and oblong or oval ; wing of the fruit narrower than or 

 .sometimes equalling the body. (B. nana, Eil. 2, not of L. A round-leaved 

 alpine form is B. rotundifolia, S/xirh., and B. Littclliana, Turkerman.) — High 

 mountains, Northern New England and New York, and shore of Lake Superior 

 and northward. — The resinous-glandular branches chiefly distinguish some of 

 the larger forms from B. pumila, and the small' alpine ones from B. nana, L. 

 of Europe : probably they run together. 



2. ALNUS, Tonrn. Ai.r.ER. 



Sterile catkins elongated and drooping, with 4 or 5 bractlcts and 3 (rarely 6) 

 flowers under each short-stalked shield-shaped scale ; each flower usually with 

 a 3 - 5-parted calyx aiid as many stamens : filaments short and simple : anthers 

 2-celled. Fertile catkins ovoid or oblong ; the fleshy scales each 2-3-flowcred, 

 with a calyx of four little scales adherent to the scales or bracts of the catkin, 

 which are thick and woody in fruit, wedgc-obovate, truncate, or 3-5-lobed, and 

 persistent. — Shrubs or small trees, with few-scaled leaf-buds, and solitary or 

 often racctuose-clustered catkins, terminating leafless branchlets or peduncles. 

 (The ancient Latin name.) 



§ \. Flowers developed in spring ivith the leaves; the sterile from catkins which hare 

 remained naked over winter ; while the. fertile have been enclosed in a scaly bud: 

 fruit with a conspicuous thin winc), as in Birch. 



1. A. viridis, DC. (Green or Mountain Alder.) Leaves round- 

 oval, ovate, or slightly heart-.shaped, glutinous and smooth or .softly downy 

 underneath, serrate with very sharp and closely set teeth, on young shoots often 



