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sandbar willow

autumn willow

Habit Shrubs or trees, 4–9 m. Stems: branches gray-brown to red-brown, glabrous or villous; branchlets yellow brown to red-brown, densely tomentose or villous to glabrescent. Shrubs, 1–5 m. Stems: branches usually flexible at base, sometimes 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 on early ones, rudimentary or foliaceous on late ones;

petiole 1–5(–9) mm, glabrous or sparsely villous adaxially;

largest medial blade linear to lorate, 60–160 × 4–11 mm, (6.5–)11–19(–31) times as long as wide, base cuneate, margins flat, remotely spinulose-serrulate (teeth 2–5 per cm), apex acute or subacuminate, abaxial surface thinly glaucous, densely villous or long-silky to glabrescent, adaxial slightly glossy, pilose or densely villous to glabrescent;

proximal blade margins entire;

juvenile blade reddish or yellowish green, moderately densely to sparsely long-silky abaxially.

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.

Staminate flowers

abaxial nectary 0.5–1.1 mm, adaxial nectary ovate, narrowly oblong, or flask-shaped, 0.6–1.4 mm, nectaries distinct;

filaments hairy;

anthers 0.4–0.9 mm.

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 narrowly oblong, 0.4–1.1 mm, shorter to longer than stipe;

stipe 0.4–0.8 mm;

ovary obclavate to pyriform, glabrous, glabrescent, or long-silky, beak abruptly tapering to styles;

ovules 16–36 per ovary;

styles 0–0.2 mm;

stigmas flat, abaxially non-papillate with pointed tip, or broadly cylindrical, 0.3–0.7 mm.

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

(4–)5–8(–10) mm.

7–12 mm.

Catkins

(flowering throughout season); staminate 20–61 × 4–10 mm, flowering branchlet 3–20 mm; pistillate loosely flowered, slender or stout, 20–67 × 5–9 mm, flowering branchlet 3–19 mm;

floral bract (sometimes greenish), 1.5–3.5 mm, apex acute, acuminate, or rounded, entire, erose, or toothed, abaxially hairy either proximally or distally, hairs wavy.

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.

2n

= 38.

= 76.

Salix interior

Salix serissima

Phenology Flowering early Apr-early Jul. Flowering early Jun-early Jul.
Habitat Sandy to silty flood plains, margins of lakes, ponds, and prairie sloughs, dry prairie sand hills, marshes, disturbed areas Wet thickets, fens, brackish marshy strands, marly lakeshores, treed bogs, gravelly stream banks, lakeshores
Elevation 10-1800 m (0-5900 ft) 10-3000 m (0-9800 ft)
Distribution
from FNA
AK; AR; CO; CT; DC; DE; IA; IL; IN; KS; KY; LA; MD; ME; MI; MN; MO; MS; MT; ND; NE; NJ; NY; OH; OK; PA; SD; TN; TX; VA; WI; WV; WY; AB; BC; MB; NB; NT; ON; QC; SK; YT; Mexico (Tamaulipas, Veracruz)
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[BONAP county map]
from FNA
CO; CT; IL; IN; MA; MI; MN; MT; ND; NJ; NY; OH; PA; SD; VT; WI; WY; AB; BC; MB; NB; NL; NT; NU; QC; SK
[WildflowerSearch map]
[BONAP county map]
Discussion

Sometimes Salix interior is treated as a subspecies of S. exigua (R. D. Dorn 1998). Salix exigua and S. interior hybridize and apparently intergrade in the western Great Plains; because the area of overlap is relatively small and distinctiveness of the two taxa is not compromised by hybridization and introgression, it is best to treat them as separate species.

Leaves on sylleptic shoots are usually very densely silky. Salix interior sometimes has shoots that arise from buds on either side of the normal axillary bud. They do not seem to be directly related to the stipules because they are enclosed by the petiole. Catkins with both staminate and pistillate flowers are rare in S. interior, but a Quebec specimen had some catkins predominantly pistillate and others staminate; most were a mixture. The flowers were not teratological, but a mature capsule contained aborted ovules.

Hybrids:

Salix interior forms natural hybrids with S. exigua var. exigua. Controlled pollinations using S. interior (as S. exigua) from southern Ontario (A. Mosseler 1990) successfully produced F1 hybrids with S. bebbiana, S. discolor, S. eriocephala, and S. petiolaris. Seed production was usually relatively low, except in crosses with S. discolor. In general, F1 viability was relatively low in crosses with these members of subg. Vetrix. No seeds were produced in crosses with members of subgenera Protitea or Salix. Morphology of the hybrids usually was intermediate between the two parents, but when S. petiolaris was used as the maternal parent, the F1s more closely resembled that species. J. Salick and E. Pfeffer (1999) extended these findings to show that, although crosses between S. interior (as S. exigua) and S. eriocephala are partially sterile, their clonal growth parameters (sprouting, shoot length, and biomass production) are strong and thus permit these partially sterile hybrids to exist as successful individuals and perhaps to “... make a contribution to interspecific gene flow over time.” Of particular taxonomic interest is that, in this cross, the staminate parent has a significant influence on leaf shape, whereas in the cross S. eriocephala × S. petiolaris it is the pistillate parent that is significant for leaf shape. Relatively few hybrids resembling those produced by Mosseler have been recognized in nature, but it is possible that the unusually broadly leaved plants named S. interior var. exterior and var. wheeleri, from northern Maine, Nebraska, New York, and West Virginia, and probably elsewhere, may be hybrids. Phenological isolation may be strong enough to prevent crosses in nature (A. Mosseler and C. S. Papadopol 1989) with the earlier flowering S. eriocephala and S. petiolaris, a barrier that even an occasional period of overlap cannot breach.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Salix serissima is found in Nunavut only on Akimiski Island in James Bay.

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).

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:

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

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 7, p. 56. FNA vol. 7, p. 45.
Parent taxa Salicaceae > Salix > subg. Longifoliae Salicaceae > Salix > subg. Salix > sect. Salicaster
Sibling taxa
S. alaxensis, S. alba, S. amygdaloides, S. arbusculoides, S. arctica, S. arctophila, S. argyrocarpa, S. arizonica, S. athabascensis, S. atrocinerea, S. aurita, S. babylonica, S. ballii, S. barclayi, S. barrattiana, S. bebbiana, S. bonplandiana, S. boothii, S. brachycarpa, S. breweri, S. calcicola, S. candida, S. caprea, S. caroliniana, S. cascadensis, S. chamissonis, S. chlorolepis, S. cinerea, S. columbiana, S. commutata, S. cordata, S. daphnoides, S. delnortensis, S. discolor, S. drummondiana, S. eastwoodiae, S. elaeagnos, S. eriocephala, S. euxina, S. exigua, S. famelica, S. farriae, S. floridana, S. fuscescens, S. geyeriana, S. glauca, S. gooddingii, S. hastata, S. herbacea, S. hookeriana, S. humboldtiana, S. humilis, S. irrorata, S. jejuna, S. jepsonii, S. laevigata, S. lasiandra, S. lasiolepis, S. lemmonii, S. ligulifolia, S. lucida, S. lutea, S. maccalliana, S. melanopsis, S. monochroma, S. monticola, S. myricoides, S. myrsinifolia, S. myrtillifolia, S. nigra, S. niphoclada, S. nivalis, S. nummularia, S. orestera, S. ovalifolia, S. pedicellaris, S. pellita, S. pentandra, S. petiolaris, S. petrophila, S. phlebophylla, S. planifolia, S. polaris, S. prolixa, S. pseudomonticola, S. pseudomyrsinites, S. pulchra, S. purpurea, S. pyrifolia, S. raupii, S. reticulata, S. richardsonii, S. rotundifolia, S. scouleriana, S. sericea, S. serissima, S. sessilifolia, S. setchelliana, S. silicicola, S. sitchensis, S. sphenophylla, S. stolonifera, S. taxifolia, S. thurberi, S. tracyi, S. triandra, S. turnorii, S. tweedyi, S. tyrrellii, S. uva-ursi, S. vestita, S. viminalis, S. wolfii, S. ×fragilis, S. ×jesupii, S. ×pendulina, S. ×sepulcralis, S. ×smithiana
S. alaxensis, S. alba, S. amygdaloides, S. arbusculoides, S. arctica, S. arctophila, S. argyrocarpa, S. arizonica, S. athabascensis, S. atrocinerea, S. aurita, S. babylonica, S. ballii, S. barclayi, S. barrattiana, S. bebbiana, S. bonplandiana, S. boothii, S. brachycarpa, S. breweri, S. calcicola, S. candida, S. caprea, S. caroliniana, S. cascadensis, S. chamissonis, S. chlorolepis, S. cinerea, S. columbiana, S. commutata, S. cordata, S. daphnoides, S. delnortensis, S. discolor, S. drummondiana, S. eastwoodiae, S. elaeagnos, S. eriocephala, S. euxina, S. exigua, S. famelica, S. farriae, S. floridana, S. fuscescens, S. geyeriana, S. glauca, S. gooddingii, S. hastata, S. herbacea, S. hookeriana, S. humboldtiana, S. humilis, S. interior, S. irrorata, S. jejuna, S. jepsonii, S. laevigata, S. lasiandra, S. lasiolepis, S. lemmonii, S. ligulifolia, S. lucida, S. lutea, S. maccalliana, S. melanopsis, S. monochroma, S. monticola, S. myricoides, S. myrsinifolia, S. myrtillifolia, S. nigra, S. niphoclada, S. nivalis, S. nummularia, S. orestera, S. ovalifolia, S. pedicellaris, S. pellita, S. pentandra, S. petiolaris, S. petrophila, S. phlebophylla, S. planifolia, S. polaris, S. prolixa, S. pseudomonticola, S. pseudomyrsinites, S. pulchra, S. purpurea, S. pyrifolia, S. raupii, S. reticulata, S. richardsonii, S. rotundifolia, S. scouleriana, S. sericea, S. sessilifolia, S. setchelliana, S. silicicola, S. sitchensis, S. sphenophylla, S. stolonifera, S. taxifolia, S. thurberi, S. tracyi, S. triandra, S. turnorii, S. tweedyi, S. tyrrellii, S. uva-ursi, S. vestita, S. viminalis, S. wolfii, S. ×fragilis, S. ×jesupii, S. ×pendulina, S. ×sepulcralis, S. ×smithiana
Synonyms S. rubra, S. exigua var. exterior, S. exigua subsp. interior, S. exigua var. pedicellata, S. exigua var. sericans, S. fluviatilis var. sericans, S. interior var. exterior, S. interior var. pedicellata, S. interior var. wheeleri, S. linearifolia, S. longifolia var. interior, S. longifolia var. pedicellata, S. longifolia var. sericans, S. longifolia var. wheeleri, S. wheeleri S. lucida var. serissima
Name authority Rowlee: Bull. Torrey Bot. Club 27: 253. (1900) (L. H. Bailey) Fernald: Rhodora 6: 6. (1903)
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