Northern Ontario Plant Database

The Genus Salix: Willows have slender branches with alternate leaves, winter buds have a single bud scale. The small, unisexual flowers lack sepals and petals, and are arranged on erect to pendant catkins (aments). Plants are dioecious, with unisexual male and female flowers borne on separate plants. Male flowers usually have 2 stamens, female flowers have a single pistil; both have a basal nectary and are subtended by a scaly bract, often bearing long silky hairs. The fruit is a small narrow conical to ovoid or pear-shaped capsule, with the top portion prolonged into a narrower beak The capsule splits into 2 halves, with each side curving backward to release the woolly seeds.

General: A low, deciduous shrub to 1 m tall; young twigs yellowish to olive or reddish, mature twigs reddish to gray-brown, smooth.

Leaves: Alternate, simple, pinnately-veined, petiolate. Leaf blade narrowly elliptic-oblong to oblanceolate, usually 2–5 cm long, to 2 cm wide; green above, paler and glaucous beneath; base tapering (cuneate) or rounded; apex pointed (acute) or blunt to rounded, occasionally mucronate; margins entire or turned under (revolute); petiole 2–6 mm long; stipules lacking.

Flowers: Unisexual, male and female catkins (aments) on different shrubs (plants dioecious); catkins are borne on short leafy branches and appear with the leaves. Staminate catkins to 2 cm long; pistillate catkins 1–5 cm long, yellow to reddish-brown. Bracts oblong, 1 mm long, yellow to brown, hairy towards the tip.

Fruit: A cluster of narrow-conical capsules, each 6–8 mm long, smooth (glabrous), borne on a short stalk (stipe), 2–4 mm long.

Habitat and Range: Bogs, swamps, and fens. The bog willow, a boreal North American species, can be found throughout northern Ontario.

Internet Images: Salix pedicellaris from the Wisconsin Vascular Plant Species website, Univ. of Wisconsin - Madison.

Charts comparing traits of the 6 common willows found in the northern Ontario FECs.

	Salix humilis (upland willow)	Salix pedicellaris (bog willow)	Salix petiolaris (slender willow)
leaf shape	oblanceolate to obovate, 3–10 cm long	narrow elliptic-oblong to oblanceolate, 2–5 cm long	linear-lanceolate to oblanceolate, 2–7 cm long
leaf margins	entire to barely crenate, + revolute	entire, slightly revolute	finely serrate, sometimes entire
lower leaf surface	gray-pubescent	glaucous	glaucous
stipules present or absent	present, deciduous	absent	absent
capsule shape & size	ovoid, long beaked, 6–9 mm long	narrow-conical, 6–8 mm long	narrow, long-beaked, 5–7 mm long
capsule pubescent or glabrous	gray-pubescent	glabrous	silvery- pubescent
catkin scales	pale	yellowish	yellowish-brown

	Salix planifolia (tealeaf willow)	Salix discolor (pussy willow)	Salix bebbiana (beaked willow)
leaf shape	elliptic to oblanceolate, 2–7 cm long	elliptic to oblanceolate, 3–10 cm long	elliptic, oblong, oblanceolate, 3–10 cm long
leaf margins	entire to barely crenate, + revolute	crenate to serrate	variable; entire, crenate, or serrate
lower leaf surface	early rusty pubescence, later glaucous	early rusty pubescence, later glaucous	gray-pubescent, often glabrate, then glaucous
stipules present or absent	present, deciduous	present, somewhat persistent	absent or small, deciduous
capsule shape & size	ovoid, short beaked, 5–7 mm long	narrow, long-beaked, 7–12 mm long	narrow, long-beaked, 7–10 mm long
capsule pubescent or glabrous	short-pubescent with fine, silky hairs	short-pubescent with fine, soft hairs	gray-pubescent
catkin scales	brown to black	brown to black	greenish-yellow, red-tipped

Similar Species: For further information on willows, see the webpages on Salix bebbiana (beaked willow), Salix discolor (pussy willow), and Salix humilis (upland willow), from the borealforest.org website, or the Salicaceae family webpage on the Aquatic and Wetland Vascular Plants of the Northern Great Plains website, part of the USGS Northern Prairie Wildlife Research Center network.

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