Sorbus scopulina

Greene

Pittonia 4: 130. 1900.

Common names: Rocky Mountain or Cascade or Greene's mountain ashE
Endemic
Synonyms: Sorbus andersonii G. N. Jones S. angustifolia Rydberg S. cascadensis G. N. Jones S. dumosa Greene S. scopulina var. cascadensis (G. N. Jones) C. L. Hitchcock
Treatment appears in FNA Volume 9. Treatment on page 442. Mentioned on page 435, 443, 444, 651.

Shrubs, 10–50 (–80) dm. Stems 1–8; bark gray, sometimes yellowish or reddish purple, or grayish red; winter buds olive brown to redbrown, conic, 8–14 mm, shiny, slightly glutinous, glabrous or sparsely or densely whitish-villous. Leaves pinnately compound; stipules deciduous or persistent, hairs whitish; blade paler abaxially, shiny, green to dark green adaxially, leaflets 7–13 (–15), opposite or subopposite, lanceolate, oblong, narrowly ovate, oblanceolate, or obovate, (3–) 4–6.5 (–8.7) × 1.5–2.7 cm, l/w ratio 2.1–4.4, margins finely serrate, apex obtuse, acute, or acuminate, surfaces glabrous, leaf and leaflet axils hairy, hairs whitish. Panicles 40–200+-flowered, flat-topped to rounded, 5–15 cm diam.; peduncles sparsely to densely whitish-villous. Pedicels sparsely to densely whitish-villous (in flower and fruit). Flowers 11–13 mm diam.; hypanthium nearly glabrous or densely villous, hypanthium plus sepals 3–4 mm; sepals 0.8–2.3 mm, margins lightly to densely whitish-villous, glands absent or sparse and usually inconspicuous; petals white, ovate, 4–6 mm; stamens (14–) 20; carpels distinct, apex conic, styles 3 or 4, 2–2.5 mm. Infructescences whitish-villous, rarely glabrous with age. Pomes bright orange to reddish orange, globose, subglobose, broadly obovoid, or broadly elliptic, 8–12.1 × 7.5–12.8 mm, shiny, sometimes lightly glaucous; sepals inconspicuous, incurved. Seeds brown, narrowly ovoid, 3.8–5.4 × 1.7–2.8 mm, slightly asymmetric, slightly flattened. 2n = 34, 68.


Phenology: Flowering spring; fruiting fall.
Habitat: Mountain slopes, open forests, forest edges, riparian zones, lakeshores
Elevation: 0–3300 m

Distribution

V9 744-distribution-map.jpg

Alta., B.C., N.W.T., Sask., Yukon, Alaska, Ariz., Calif., Colo., Idaho, Mont., Nev., N.Mex., Oreg., S.Dak., Utah, Wash., Wyo.

Discussion

Sorbus scopulina is variable, especially in leaflet shape, number, and indument. Plants with narrower leaflets were separated as S. angustifolia; plants with broader leaflets were segregated as S. andersonii and S. cascadensis. Densely hairy forms were named S. dumosa. All represent points on a morphologic continuum, united by their shiny leaflets, whitish indument, and western range. Sparsely hairy forms approach the more southern S. californica but have whitish axillary hairs and larger leaflets than that species, which has rufous axillary hairs and leaflets less than 4 cm. Most S. scopulina have shiny hypanthia and fruits. Occasional collections, all within the range of S. sitchensis, are glaucous-fruited. This may be natural variation, or it could represent introgression from S. sitchensis. H. A. McAllister (2005, pers. comm.) found that individuals of S. scopulina from cordilleran Idaho and Arizona were sexual diploids; plants from the Cascade and Coast ranges of British Columbia and Washington were tetraploid and presumably apomictic. Here, these entities are synonymized, awaiting a larger study that might correlate distinct morphologic characteristics with the ploidy levels. J. J. Aldasoro et al. (1998, 2004) noted that some European Sorbus species are both diploid and tetraploid, suggesting that sexual species occasionally produce spontaneous agamospermous individuals.

The intergeneric hybrid ×Amelasorbus jackii Rehder [Amelanchier alnifolia (Nuttall) Nuttall ex M. Roemer × Sorbus scopulina] has been collected in Idaho and Oregon. Foliage of the Idaho collection is very similar to that of Amelanchier, with basal pinnae inconspicuous and infrequent, suggesting that this hybrid may be overlooked.

The illegitimate later homonym Sorbus alaskana G. N. Jones pertains here.

Selected References

None.

Lower Taxa

None.
... more about "Sorbus scopulina"
Peter F. Zika +  and Stéphane M. Bailleul +
Greene +
grayish red +, reddish purple +, yellowish +  and gray +
compound +  and simple +
opposite +  and alternate +
not +  and clawed +
green +  and dark green +
ovate +  and oblong +
5 cm50 mm <br />0.05 m <br /> (33 cm330 mm <br />0.33 m <br />) +
? (?) +  and ? (?) +
glutinous +
olive brown +  and redbrown +
whitish-villous +, or +  and glabrous +
0.8 cm8 mm <br />0.008 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
odd +  and simple +
divided +  and lobed +
tanniferous +
Rocky Mountain or Cascade or Greene's mountain ashE +
Alta. +, B.C. +, N.W.T. +, Sask. +, Yukon +, Alaska +, Ariz. +, Calif. +, Colo. +, Idaho +, Mont. +, Nev. +, N.Mex. +, Oreg. +, S.Dak. +, Utah +, Wash. +  and Wyo. +
not +  and aggregated +
0–3300 m +
single-layered +
1.1 cm11 mm <br />0.011 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
rancid +, unpleasant +  and strong +
unisexual +  and bisexual +
not +  and aggregated +
not +  and aggregated +
yellow +, brown +, red +  and orange +
glabrous +, hairy +  and glaucous +
0.4 cm4 mm <br />0.004 m <br /> (1.9 cm19 mm <br />0.019 m <br />) +
inconspicuous +
Mountain slopes, open forests, forest edges, riparian zones, lakeshores +
green +  and red +
villous +  and glabrous +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
glabrous +  and whitish-villous +
crassinucellate +
deciduous +
subopposite +  and opposite +
1.5 cm15 mm <br />0.015 m <br /> (2.7 cm27 mm <br />0.027 m <br />) +
papillose +
obovate +, oblanceolate +, ovate +, oblong +  and lanceolate +
whitish-villous +
toothed +, unlobed +  and lobed +
inferior +  and superior +
biseriate +  and clustered +
collateral +  and basal +
3 +  and 2 +
40-200+-flowered +
5 cm50 mm <br />0.05 m <br /> (15 cm150 mm <br />0.15 m <br />) +
hairy +, glaucous +  and glabrous +
flat-topped +  and rounded +
whitish-villous +
whitish-villous +
0 (?) +  and 4 (?) +
free +  and distinct +
2 +  and 5 +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Flowering spring +  and fruiting fall. +
adnate +, free +, connate +  and distinct +
bright orange +  and reddish orange +
0.8 cm8 mm <br />0.008 m <br /> (1.21 cm12.1 mm <br />0.0121 m <br />) +
elliptic +, obovoid +, subglobose +  and globose +
0.75 cm7.5 mm <br />0.0075 m <br /> (1.28 cm12.8 mm <br />0.0128 m <br />) +
not arillate +
0.38 cm3.8 mm <br />0.0038 m <br /> (0.54 cm5.4 mm <br />0.0054 m <br />) +
flattened;ovoid +
0.17 cm1.7 mm <br />0.0017 m <br /> (?) +  and 0.28 cm2.8 mm <br />0.0028 m <br /> (?) +
persistent +
free +  and distinct +
inconspicuous +
triangular +  and ovate +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.23 cm2.3 mm <br />0.0023 m <br />) +
free +  and distinct +
branched +  and simple +
ascending +  and erect +
1 +  and 8 +
persistent +  and deciduous +
short-adnate +  and free +
persistent +
distinct +
basal +, lateral +, subterminal +  and terminal +
elongate +
0.2 cm2 mm <br />0.002 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
Sorbus andersonii +, S. angustifolia +, S. cascadensis +, S. dumosa +  and S. scopulina var. cascadensis +
Sorbus scopulina +
Sorbus sect. Commixtae +
species +
inconspicuous +
hairy +  and glabrous +