Flora of North America species comparison

branches (sometimes ± brittle at base), yellow-green, gray-brown, red-brown, or violet, usually glaucous, glabrous or sparsely tomentose;

branchlets yellowish, yellow-brown, red-brown, or violet, (strongly glaucous or not), glabrous or sparsely to moderately densely pubescent, (buds caprea-type).

stipules usually absent or rudimentary (rarely foliaceous);

petiole convex to flat, or shallowly to deeply grooved adaxially, 2–9 mm, velvety, short-silky, or pubescent adaxially;

largest medial blade lorate, narrowly elliptic, or linear, 32–89 × 5.5–14 mm, 3.6–8.4(–11.3) times as long as wide, base cuneate or convex, margins flat or slightly revolute, entire or distantly and shallowly serrulate, apex acute to acuminate, abaxial surface glaucous, glabrous or densely short- or long-silky, hairs (white, sometimes also ferruginous), straight, adaxial slightly glossy, densely short- or long-silky, especially midrib, to glabrescent, (hairs white, sometimes also ferruginous);

proximal blade margins entire or distantly and shallowly serrulate;

juvenile blade reddish or yellowish green, densely to sparsely long- or short-silky abaxially, hairs white, sometimes also ferruginous.

stipules absent or rudimentary on early ones, foliaceous or rudimentary on late ones;

petiole 1–5(–10) mm, pubescent or puberulent, villous, or short-silky adaxially;

largest medial blade (sometimes hypostomatous), linear or lorate, (glands marginal), 30–136–143 × 2–14 mm, 6.5–28(–37.5) times as long as wide, base cuneate, margins slightly revolute, entire or remotely spinulose-serrulate, apex acuminate or acute, abaxial surface glaucous (sometimes obscured by hairs), densely long-silky, villous or pilose to glabrescent, hairs appressed or spreading, straight or wavy, adaxial slightly glossy, sparsely or densely long-silky to glabrescent;

proximal blade margins entire;

juvenile blade yellowish green, densely long-silky-villous abaxially.

adaxial nectary oblong, ovate, or square, 0.3–0.8(–0.9) mm;

filaments distinct, glabrous or hairy on proximal 1/2 or basally;

anthers yellow or purple turning yellow, ellipsoid or globose, 0.4–0.5(–0.6) mm.

abaxial and adaxial nectaries present and distinct;

filaments hairy on proximal 1/2;

anthers (sometimes reddish turning yellow).

adaxial nectary oblong, square, or ovate, 0.2–1 mm;

stipe (0.4–)1–2.8 mm;

ovary pyriform (gourd-shaped), beak gradually tapering to styles;

ovules 6–12 per ovary;

styles 0.1–0.2(–0.6) mm;

stigmas flat, abaxially non-papillate with rounded or pointed tip, 0.2–0.3–0.44 mm.

adaxial nectary oblong, ovate, or flask-shaped, relative adaxial nectary/stipe length variable even within same catkin;

stipe 0–0.9 mm;

ovary obclavate or pyriform, glabrous, pilose, or villous, or sometimes beak hairy, beak bulged below or abruptly tapering to styles;

ovules 12–30 per ovary;

styles (sometimes distinct), 0–0.5 mm;

stigmas flat, abaxially non-papillate with rounded tip, or 2 plump lobes, 0.1–0.5 mm.

(3–)4–6 mm.

4–8 mm.

flowering (before or) as leaves emerge; staminate globose, (1–1.1–)11–18 × 6–11 mm, flowering branchlet 1–5 mm; pistillate densely to loosely flowered, subglobose to globose, 8–21 × 7–17 mm, flowering branchlet 0.5–8 mm;

floral bract tawny or brown (black), 1.2–2.8 mm, apex rounded or acute, abaxially hairy, hairs short, wavy or straight.

staminate 7–54 × 2–10 mm, flowering branchlet 1.5–56 mm; pistillate loosely to densely flowered, slender or stout, 14.5–70 × 3–12 mm, flowering branchlet 2–55 mm;

floral bract 1.2–2.6 mm, apex acute, convex, or rounded, entire or erose, hairs wavy, straight, or crinkled, abaxially hairy throughout or proximally, or glabrate.

= 38.

= 38.