Salix triandra L.

Current year's branchlets glabrous to sparsely tomentose, slightly ribbed, greyish red (UCL19). Year-old branchlets glabrous, greyish olive (UCL111). Flower buds 5 mm long, ovoid, keels absent, glabrous. Leaf buds sparsely to densely tomentose or long-silky hairy, hairs sometimes brown. Leaves alternate. Stipule persistent, 4.5–11 mm long, asymmetrically narrowly ovate with an obvious auricle at base. Petiole 10–37 mm long, sparsely to moderately densely tomentose, pinky red, with 2–4 brown, green, or pinky-red glands in clusters, base not enlarged. Emerging leaves green or tinged with orange, sparsely tomentose, the tomentum soon lost. Proximal leaf margins with rows of glands. Leaf lamina 65–115 mm long, 11–21 mm wide, length to width ratio 4.4–6.8:1, narrowly oblong to very narrowly ovate, not falcate; base cuneate or rounded; apex very narrowly acute, occasionally acuminate; leaf galls absent; margins densely serrulate, flat or occasionally finely revolute; upper lamina surface very slightly bullate due to impressed veins, slightly glossy, glabrous; stomata absent, dense only near margin, or dense over the whole surface; lower lamina surface midvein raised, netted veins usually visible, not glaucous or distinctly glaucous (in 'Semperflorens'), glabrous. Catkins male, opening coetaneously with leaves. Flowering branch 50–64 mm long with 4–6 leaves. Male catkin 30–95 mm long, 8 mm diameter; catkin rachis not visible between flowers. Flower bracts 2.1–2.5 mm long, 1.1–1.6 mm wide, pale yellow-green, slightly red at the obtuse apex, flat, densely tomentose all over. Male nectaries 2, 0.40 mm long, 0.44 mm wide, yellow-green. Stamens 3, filaments free, hairs present at base; anthers 0.7–0.8 mm long, yellow. Female catkin 23–33 mm long, 4–6 mm diameter; catkin rachis not visible between flowers. Flower bract 1.7–2.0 mm long, 1.1 mm wide, pale yellow-green, flat; apex obtuse, long-silky hairs moderately dense on surfaces and margins. Female nectary 1, rectangular, 0.34 mm long, 0.42 mm wide, yellow; ovary 1.8–2.0 mm long, glabrous; stipe 1.1 mm long; ovary extending well beyond flower bract, style arms dividing directly at top of ovary, style arms 0.4 mm long, unlobed, stigmatic surfaces hyaline.

Leaves oblong; apex very narrowly acute, finely serrate, with a petiole 10–36 mm long. The lamina is usually about 95 × 20–22 mm, glaucous below, moderately glossy above, with netted veins visible on both surfaces (resembling the leaf venation of a New Zealand Gaultheria), but veins are not raised. Male catkins are long and pendulous, and each flower has 3 yellow anthers, the flower bract is pale yellow-green, densely villous, spathulate with an obtuse apex. Red leaf galls may be present and abundant (unusual for a shrub willow). Stipules are asymmetrically ovate and have a large auricle at the base. Petiole glands are in clusters. Ovaries are glabrous and the style arms divide directly at the apex of the ovary and are unlobed.

Most similar to Salix nigra in having long, narrow, pendulous catkins when fully open, and in having more than 2 anthers per flower. The leaves of Salix triandra are more obviously toothed than those of S. nigra and are thicker in texture.

There are 6 cultivars of Salix triandra at Aokautere and Massey: 'Black German' (PN374), 'Black Maul' (PN606), 'Brunette Noir' (PN378), 'Noir de Villaine' (PN608), 'Stone Rod' (PN377), and 'Semperflorens'. 'Semperflorens' is unusual in flowering for 9 months of the year (Newstrom-Lloyd, pers. comm., 2017), in having leaves glaucous on the leaf underside, and in sometimes having a small pair of leaflets at the distal end of the petiole.

First collection: CHR 426409, B. J. Donovan, 15 February 1989, Halswell garden.

First publication: Otago Witness 1881.

Flowering: Late September–early December.

Variably diploid, triploid, or pentaploid (Argus 2010). Flow cytometry provisionally indicates cultivars in New Zealand are mostly diploid, the exception being 'Stone Rod', which is tetraploid.