BETULACEAE - - Birch Family

Alnus viridis (Villars) Lamarck & De Candolle ssp. crispa (Aiton) Turrill — Green or Mountain Alder

Green Alder (Alnus viridis ssp. crispa) is a shrub or small tree to 3 m., sometimes decumbent; leaves ovate or broad-elliptic, 3-8 cm. long, acute, usually rounded or slightly subcordate at base, margins undulate and rather coursely toothed, glabrous beneath to slightly pubescent on the main veins; stalks of female catkins (cones) pubescent; cones 3-6, racemose, 1-1.5 cm. long, on stalks 5-15 mm. long. The species name viridis means green, and the sub-species name crispa means with curled or wavy margins.

Separating Characteristics

An obvious separating character, here in the south is habitat / range, since this species is more northern and only found at Roan Mountain on the border of NC and TN. And, Weakley ("Flora of the Southern and Mid-Atlantic States," Working Draft of 30 November 2012) separates this from the other species of Alder by this character: Fruit broadly winged; winter buds sessile, covered by multiple, imbricate, unequal scales.

Habitat

Grassy balds, shrub balds, spruce-fir forests, and rock outcrops at high elevations (1600-1900m) in the Roan Mountain Massif, Mitchell and Avery counties, NC and Carter County, TN., locally common.

Habitat information from:
Weakley, Alan S., Flora of the Southern and Mid-Atlantic States, Working Draft of 21 May 2015.

Native Range

Ssp. crispa is generally far northern, ranging across n. Canada, south to MA and c. NY, and disjunct at a few localities in PA and at Roan Mountain on the NC-TN border, where it forms an extensive population (which is where these photos were taken).

The native range of Alnus viridis ssp. crispa (Green or Mountain Alder)

Kartesz, J.T., The Biota of North America Program (BONAP). 2015. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)].