326 CUPULIFERiE. 



Mountain bogs. Can. N. Y. and Penn. Pursh. W. to Ohio. May, Jvine. 

 ^2. — Stem 2 — 3 (eat high. Leaves on short petioles, somewhat pubescent be- 

 neath. Dr. Torrey states that he has seen no specimens collected in New York. 



Low Birch. 

 7. B. nana Linn. ; very smooth ; leaves orbicular, crenate, reticular- 

 veined beneath ; fertile aments oblong, on short peduncles ; scales deeply 

 3-parted ; lobes oblong-obovate, nearly equal. 



White Mountains, N. H. High mountains of Essex county, N. Y. N. to 

 Hudson's Bay. April, May. T7. — Stem 1 — 2 feet high, branched. Leaves small. 

 Fertile aments half an inch long. Fruit ovate, with a winged margin. 



Dwarf Birch. 

 2. ALNUS. Willd.— Alder. 



(From the Celtic al, near, and Ian, the river bank.) 



Monoecious. Sterile Fl. Ament long, cylindric ; scales 

 3-lobed, 3 -flowered. Perianth 4-parted. Stamens 4. Fertile 

 Fl. Ament ovoid ; scales subtrifid, 2-flowered. Perianth none. 

 Styles 2. Nut compressed. 



1 A. semdata Willd. : leaves obovate, somewhat coriaceous, doubly ser- 

 rulate, acuminate, veins and their axils hairy beneath ; stipules oval, ob- 

 tuse. 



Swamps and banks of rivers. Can. to Car. March. Yi- — Stem 6—10 feet 

 high, with alternate leaves. Sterile flowers in a long pendulous ament ; fertile 

 ones about half an inch long, thick and rigid, purplish-brown, persistent, often 

 somewhat clustered. Common Alder. 



2. A. incana Willd. : leaves thin, ovate or oblong, rather acute, obtuse 

 or somewhat cordate at base, slightly lobed, acutely serrate, glaucous and 

 pubescent beneath, naked in the axils of the veins ; stipules oblong-lance- 

 olate.* {Torr. N.Y. Fl.) A. crispa Pursk, (in part.) A. glauca Mich. f. 

 . Banks of mountain streams. Can. N. Eng. N. Y. Yi. — Stem 8 — 20 feet 

 high, with smooth brown bark. Fertile aments oval, usually 4 — 5 in a panicu- 

 late raceme. Black Alder. 



3.Aviridis D.C. : leaves oval or ovate, obtuse or acute, somewhat obtuse 

 at the base, doubly serrate, glutinous and pubescent beneath, or only the 

 veins and axils pubescent ; stipules broad-ovate ; fruit witli a broad winged 

 margin. ( Torr. N. Y. Fl.) A. undulata Willd. Betula crUpa Ait. 



Banks of mountain streams. Ver. N. H. and N. Y. N. to Hudson's Bay- 

 W. to the N. W. coast. T^ — ^^^'"^ 4 — 8 feet high, much branched ; the branches 

 warty. Fertile aments ovoid, obtuse, three-fourths of an inch long, on long pedi- 

 cels. Fruit winged, like that of a Betula. Mountain Adder. 



Orde{i CXVIII. CUPULIFER.^.— Nuts. 



Flowers usually monoecious. Sterile Fl. in aments. Sta- 

 mens 5 — 20, inserted into the base of scale-like or regular per- 

 ianth. Fertile Fl. solitary, 2 — 3 together or clustered. Ovary 

 crowned by the rudiments of an adherent perianth, seated within 

 a coriaceous involucre which is usually echinate or scaly exter- 

 nally, and encloses the fruit at maturity or forms a cup at its 



