2. ÁLNUS, Tourn. Alder.
Sterile catkins elongated and drooping, with 4 or 5 bractlets and 3 (rarely 6) flowers upon each short-stalked shield-shaped scale; each flower usually with a 3–5-parted calyx and as many stamens; filaments short and simple; anthers 2-celled. Fertile catkins ovoid or oblong; the fleshy scales each 2–3-flowered, with a calyx of 4 little scales adherent to the scales or bracts of the catkin, which are thick and woody in fruit, wedge-obovate, truncate, or 3–5-lobed, and persistent.—Shrubs or small trees, with few-scaled leaf-buds, and solitary or often racemose-clustered catkins, terminating leafless branchlets or peduncles. (The ancient Latin name.)
§ 1. Flowers developed in spring with the leaves; the sterile from catkins which have remained naked over winter; while the fertile have been enclosed in a scaly bud; fruit with a conspicuous thin wing, as in Birch.
1. A. víridis, DC. (Green or Mountain Alder.) Shrub 3–8° high; leaves round-oval, ovate, or slightly heart-shaped, glutinous and smooth or softly downy beneath, irregularly serrulate or biserrulate with very sharp and closely set teeth, sometimes sinuate-toothed and serrulate (var. sinuàta, Regel), on young shoots often cut-toothed; fertile catkins slender-stalked, clustered, ovoid (6–8´´ long).—On mountains and mountain streams, Newf. to W. Mass., N. Y., L. Superior, and far north and west; also in the Alleghanies to N. C. (Eu., Asia.)
§ 2. Flowers developed in earliest spring, before the leaves, from mostly clustered catkins which (of both sorts) were formed the foregoing summer and have remained naked over winter; fruit wingless or with a narrow coriaceous margin.
2. A. incàna, Willd. (Speckled or Hoary A.) Leaves broadly oval or ovate, rounded at base, sharply and often doubly serrate, whitened and mostly downy beneath; stipules oblong-lanceolate; fruit orbicular.—Borders of streams and swamps, Newf. to Mass., E. Neb., Minn., and westward. Shrub or tree 8–20° high; the common Alder northward. (Eu., Asia.)
3. A. serrulàta, Willd. (Smooth A.) Leaves obovate, acute at base, sharply serrate with minute teeth, thickish, green both sides, smooth or often downy beneath; stipules oval; fruit ovate.—Borders of streams and swamps, Mass. to Fla., west to S. E. Minn. and Tex.; common. Shrub forming dense thickets, or sometimes at the south a small tree 6–35° high.
§ 3. Flowers in autumn (Sept.) from catkins of the season; the fertile mostly solitary in the axils of the leaves, ripening the fruit a year later; fruit wingless.
4. A. marítima, Muhl. (Sea-side A.) Glabrous; leaves oblong, ovate, or obovate with a wedge-shaped base, slender-petioled, sharply serrulate, bright green, or rather rusty beneath; fruiting catkins large, ovoid or oblong (9–12´´ long, 6´´ thick).—Borders of streams and swamps. S. Del. and E. Md., near the coast. Small tree 15–25° high. (E. Asia.)
3. CÓRYLUS, Tourn. Hazel-nut. Filbert.