Salix serissima (L. H. Bailey) Fernald
Family: Salicaceae
Salix serissima image
Nathanael Pilla  
Shrubs, 1-5 m. Stems: branches usually flexible at base, some-times brittle, yellow-brown, red-brown, or gray-brown, glabrous, slightly glossy or dull; branchlets yellow-brown or red-brown, glabrous, slightly or highly glossy. Leaves: stipules absent or rudimentary; petiole shallowly to deeply grooved adaxially, 3-13 mm, with pairs of spherical glands distally or throughout, glabrous adaxially; largest medial blade hypostomatous or hemiamphistomatous, narrowly oblong, very narrowly elliptic, elliptic, lanceolate, or narrowly ovate, 43-110 × 9-33 mm, 2.4-6 times as long as wide, base convex or cuneate, margins flat, serrulate, apex acuminate, caudate, or acute, abaxial surface usually not glaucous, sometimes thinly so (appearing pale green), slightly glossy, glabrous, adaxial highly glossy, glabrous; proximal blade margins serrulate or entire; juvenile blade reddish or yellowish green, glabrous abaxially. Catkins: staminate (stout), 25-53 × 12-16 mm, flowering branchlet 5-14 mm; pistillate (fruiting in autumn, often persistent) moderately densely to loosely flowered, stout to globose, 17-42(-65 in fruit) × 11-22 mm, flowering branchlet 5-32(-65 in fruit) mm; floral bract (sometimes greenish tawny), 1.2-4 mm, apex acute, rounded, or truncate, glandular-toothed, abaxially moderately densely hairy, hairs straight or wavy. Staminate flowers: abaxial nectary 0.5-1.1 mm, adaxial nectary oblong or ovate, 0.4-1.1 mm, nectaries distinct or connate and cup-shaped; stamens 3-9; filaments distinct or basally connate, hairy on proximal 1/2 or basally; anthers ellipsoid or shortly cylindrical, 0.5-0.7 mm. Pistillate flowers: adaxial nectary ovate, oblong, or flask-shaped, 0.3-1.1 mm, shorter than stipe; stipe 1.2-2.4 mm; ovary pyriform to obclavate, beak slightly bulged below or abruptly tapering to styles; ovules 12-16 per ovary; styles connate, 0.3-1 mm; stigmas flat, abaxially non-papillate with rounded tip, or slenderly cylindrical, 0.4-0.7 mm. Capsules 7-12 mm. 2n = 76. Flowering early Jun-early Jul. Wet thickets, fens, brackish marshy strands, marly lakeshores, treed bogs, gravelly stream banks, lakeshores; 10-3000 m; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., Nunavut, Que., Sask.; Colo., Conn., Ill., Ind., Mass., Mich., Minn., Mont., N.J., N.Y., N.Dak., Ohio, Pa., S.Dak., Vt., Wis., Wyo. Flowering of Salix serissima is often described as serotinous (i.e., long after leaves emerge), but actually, they flower just as leaves emerge. Although they flower only a little later in spring than related species, they set fruit in late summer, and fruiting catkins often persist throughout winter. Their seeds remain dormant throughout the winter and germinate in the spring, thus enabling them to invade fens by completing their first annual growth before the sedges and grasses are tall enough to shade them out. This strategy has been reported to occur also in the related S. pentandra (A. K. Skvortsov 1999). Salix serissima is found in Nunavut only on Akimiski Island in James Bay.

North American Salix serissima is closely related to Eurasian S. pseudopentandra (Floderus) Floderus (A. K. Skvortsov 1999), which is known in China as S. pentandra var. intermedia Nakai and possibly also S. humaensis Y. L. Chou & R. C. Chou (Fang Z. F. et al. 1999). The relationship of S. serissima and S. pseudopentandra is similar to that of S. arbusculoides and S. boganidensis (G. W. Argus 1997). These two species, along with the amphiberingian S. vestita, are relictual members of former panboreal distributions.


Hybrids between Salix lucida and S. serissima have been reported (M. L. Fernald 1950); no convincing specimens have been seen.

Shrub 1 - 4 m tall Leaves: alternate, on slender, glandular leafstalks, shiny dark green above, with a slightly waxy coating (glaucous) beneath, 5 - 10 cm long, 1 - 3.5 cm wide, lance-shaped to narrowly egg-shaped with a tapering or rounded base and pointed tip, finely toothed (teeth glandular), firm, and net-veined (beneath). Young leaves are reddish. Flowers: either male or female, borne on separate trees (dioecious) in cylindrical catkins. The catkin is hairy and grows on a short, leafy stalk. Female catkin 1.5 - 5 cm long with pale yellow scales. Ovary hairless. Male catkin 1.5 - 4 cm long with pale yellow scales. Stamens three to seven. Fruit: a capsule, in elongated clusters, short-stalked, brown, 7 - 10 mm long, and flask-shaped. Seeds have long, white, silky hairs attached. Bark: olive-brown. Twigs: shiny yellowish brown. Buds: shiny yellowish brown.

Similar species: In the Chicago Region, Salix serissima differs from most other shrub willows by having green, hairless, and finely toothed leaves that are not revolute (rolled downward along the margins). Salix lucida is similar but has very shiny upper and lower leaf surfaces, while S. serissima is slightly glaucous beneath.

Flowering: June

Habitat and ecology: In the Chicago Region, Salix serissima is rare in alkaline marshes and bogs, particularly in the northwestern sector. It is most often found in calcareous floating mats and fens.

Occurence in the Chicago region: native

Notes: An attractive shrub with glossy leaves and branches. The fruit matures in late summer to early autumn.

Etymology: Salix is the Latin word for willow. Serissima means "very late."

Author: The Morton Arboretum

From Flora of Indiana (1940) by Charles C. Deam
This is a low ground shrub and is found along streams, about lakes, and in marshes. It is local and restricted to a few counties of the northeastern part of the state.


Indiana Coefficient of Conservatism: C = 10

Wetland Indicator Status: OBL

Shrub 1-4 m, with olive-brown branches, the twigs and bud-scales yellow-brown, glabrous, shining; stipules minute or none; lvs glabrous from the first, reddish when young, firm, lanceolate to lance-elliptic or lance-oblong, 5-10 נ1-2.5(-3.5) cm, finely glandular-serrate, acute to short-acuminate, shining dark green above, subglaucous beneath; petioles glandular above at the tip; catkins with or somewhat after the lvs, the staminate 1.5-3(-4) cm, the pistillate stout, 1.5-3.5(-5) cm at maturity, on lateral leafy peduncles 1-3.5 cm; scales pale yellow, white-pilose nearly or quite throughout, those of the pistillate catkins deciduous; stamens 3-7; fr narrowly conic, 7-10 mm glabrous, on pedicels 1-2 mm; style to 1 mm; 2n=76. Swamps and bogs; Nf. to Alta., s. to n. N.Y., N.J., n. Ind., c. Minn., and Colo. Late May-June, the fr maturing in late summer or fall.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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