BETULACEAE 105 



b. Bark yellowish or silvery : leaf-blades dull above : mature bracts with 2 

 ascending lateral lobes ; nuts with orbicular-ovate wings. 



5. B. lutea. 



1. Betula populifoKa Marsh. White Birch. ( Man. p. 328 ; I. F. /. 

 J 21 1.') In moist or dry soil, N. B. to Ont., Pa. and Del. — Pennsylvania : 

 Northampton ; Monroe ; Schuyi,kii,i, ; Luzerne ; Susquehanna ; 

 Lackawanna ; Pike ; Bucks, Springfield. 



2. Betula papyrifera Marsh. Paper OR Canoe Birch. (Man. p. 

 328; I. F. /. rziz.) In woods, Newf. to Alaska, northern Pa., Mich, 

 and Wash. — Pennsylvania : Monroe ; Huntingdon ; Centre, Bear 

 Meadows ; Luzerne ; Bi,air ; Tioga ; Lackawanna. 



3. Betula nigra L. RrvER or Red Birch. (Man. p. 328; I. F. /. 

 1214.) Along streams and lakes, Mass. to Iowa, Fla. and Tex. — Pennsyl- 

 vania : Northampton ; Lancaster ; Dauphin ; Huntingdon ; Mon- 

 roe; Tioga; Chester. 



4. Betula lenta L. Cherry, Ei,ack or Sweet Birch. (Man. p. 

 328 ; I. F. _/ i2i$.) In moist soil or on hillsides, Newf. to western Ont., 

 Fla. and Tenn. — Pennsylvania: Northampton; Luzerne; Lancas- 

 ter ; York ; Franklin ; Huntingdon ; Fulton ; Monroe ; Lacka- 

 wanna ; Tioga ; Pike ; Chester ; Allegheny. 



5. Betula lutea Michx f. YELLOW or Gray Birch. (Man. p. 329 ; 

 I. F. /. 1216.) In woods, Newf. to Man., N. C. and Tenn., mainly in the 

 AUeghenies. — Pennsylvania: Monroe; Dauphin; Lancaster; Hunt- 

 ingdon ; Somerset ; Pike. 



5. AtiNUS Gaertn. 



Leaf-blades glaucous or finely tomentose beneath. i. A. incana. 



Leaf-blades green, sometimes sparingly pubescent beneath. 

 Leaf-blades finely serrate : foliage not glutinous : species native. 



2. A. rugosa. 

 Leaf-blades dentate-serrate : foliage glutinous : species naturalized. 



' Z. A. gluUnosa. 



1. Aluua incana (L.) Willd. SPECKLED OR Hoary Alder. (Man. 

 p. 330 ; I. F./. 1221.) In wet soil, Newf. to the N. W. Terr., southern 

 N. Y., Pa. and Neb. Also in En. and Asia. — Pennsylvania : Monroe, 

 Pocono Plateau; LuzERNE ; CENTRE; ERIE, Presque Isle ; SOMERSET; 

 Lackawanna ; Pike ; Northampton. 



2. Alnus rugosa (DuRoi) K. Koch. Smooth Alder. (Man. p. 330; 

 I. F.y; 1222.') In wet soil or on hillsides, Me. to Minn., Fla. and Tex. — 

 Pennsylvania : Northampton ; Luzerne ; Monroe ; Bucks ; Ches- 

 ter ; Lancaster ; Franklin ; Somerset ; Lackawanna ; Pike ; 

 Allegheny. 



3. Alnus glutinoaa (L.) Medic. European Alder. (Man. p. 330 ; 

 I. F.y. 1223.) In wet places, N. Y., Pa. and N. J., escaped from cult. 

 Native of Eu. — Pennsylvania : Northampton. 



