Flora of North America species comparison

brown tinged with red or yellow, thin, shallowly furrowed, with long, narrow ridges.

orange-brown or dark green with reddish cast, pubescent or occasionally glabrous;

lenticels reddish brown, elliptic, prominent.

ovoid, 4-6 mm, apex acute to rounded;

outer scales yellow-brown with dark margins, glabrous or with a few marginal trichomes;

leaf scars half round, bundle scars numerous, in circle.

blade ovate, often deeply and irregularly lobed, (6-)8-10 × 3-6 cm, base cuneate, truncate, or cordate, margins coarsely serrate to crenate, apex acute to short-acuminate;

surfaces abaxially glabrous or sparingly pubescent along major veins or in tufts in axils of principal lateral veins and midribs, adaxially glabrous to sparsely pubescent.

blade ovate to broadly ovate, margins entire or lobed, dentate;

venation nearly palmate.

pedunculate catkins, erect or pendent, cylindric.

staminate and pistillate on same or different plants.

staminate and pistillate on same or different plants.

sepals distinct, green with red tip, ca. 1.5 mm, pubescent;

filaments ca. 2.7 mm.

sepals 4 (4-5 in M. alba);

stamens 4, inflexed.

ovary green, ovoid, slightly compressed, ca. 2 mm, glabrous;

style branches divergent, red-brown, 0.5-1 mm;

stigma papillose.

sepals 4, green, of 2 sizes, ciliate;

ovary superior, 2-locular;

style 2-branched, branches linear.

peduncle and axis pubescent; staminate catkins 2.5-4 cm; pistillate catkins 5-8 mm.

red when immature, becoming black, purple, or nearly white, cylindric, 1.5-2.5 × 1 cm;

achenes light brown, ovoid, 2-3 mm.

short-cylindric; each achene enclosed by its enlarged, fleshy calyx.

buds surrounded by bud scales.

= 14.