Alnus 



Betulaceae 



377 



Map 777 

 Alnus rugosa (Ehrh.) Spreng. 



50 



Map 778 



Fagus grandifolia Ehrh, 



50 



Map 779 



Castanea dentata (Marsh.) Borkh. 



fera.) This is a natural hybrid. I found it in a tamarack bog about a 

 fourth of a mile north of Mineral Springs Stop on the South Shore Elec- 

 tric Line, in Porter County and in a marsh about two and a half miles 

 northwest of Porter in the same county. 



The general range is unknown. Known to occur in Mich., Ind., and 

 Minn. 



1888. ALNUS [Tourn.] Hill. Alder 



Leaves broadly elliptic to ovate, mostly rounded at the base, acute at the apex, margins 

 doubly serrate (that is, the 9-13 primary veins ending in the apices of large teeth 

 which in turn are finely serrate), glaucous, glaucescent, or green beneath, deeply 

 impressed-nerved above, not noticeably glutinous beneath ; shrubs or small trees . . . 

 1. A. incana var. americana. 



Leaves obovate, acute at the base, generally more or less rounded at the apex, some- 

 times acute, margins finely and nearly evenly serrate, green and sometimes notice- 

 ably glutinous beneath, usually not impressed-nerved above but sometimes so; 

 shrubs 2. A. ragosa. 



1. Alnus incana (L.) Moench var. americana Regel. (Alnus incana of 

 Gray, Man., ed. 7 and of Britton and Brown, Illus. Flora, ed. 2.) Speckled 

 Alder. Map 776. Frequent in low ground about sloughs in the dunes near 

 Lake Michigan and rare to very rare elsewhere in low woods or in low 

 ground along streams. All of my specimens have the leaves more or 

 less glaucous beneath and more or less pubescent, at least on the principal 

 veins. 



Newf. to Sask., southw. to Pa., Iowa, and Nebr. 



2. Alnus rugosa (Ehrh.) Spreng. (Almis rugosa (DuRoi) Spreng. of 

 Gray, Man., ed. 7, Britton and Brown, Illus. Flora, ed. 2, and Deam, 

 Shrubs of Indiana, ed. 2.) Hazel Alder. Map 777. Locally in colonies 

 but rare to infrequent in the parts of the state where it is found. It 

 inhabits springy places in woodland or in the open. Its habitat and asso- 

 ciates indicate that it requires a slightly acid soil. 



Maine to Minn., southw. to Fla. and Tex. 



