Sorbus hybrida

Linnaeus

Sp. Pl. ed. 2, 1: 684. 1762.

Common names: Oak-leaf mountain ash
Introduced
Treatment appears in FNA Volume 9. Treatment on page 438. Mentioned on page 435, 439.

Trees, 30–120 dm. Stems single or multistemmed; bark gray; winter buds brownish to purple, ovoid to ovoid-conic, 4–10 mm, dull, not glutinous, densely white-villous, at least distally and on scale margins. Leaves proximally pinnately compound, lobed distally; stipules deciduous or persistent, often white-villous; blade paler green abaxially, dull green adaxially, ovate to oblong-ovate, rarely oblong, 7–13 × 5–11 cm, pinnately lobed with (1 or) 2 (or 3) pairs of sessile or decurrent, free, oblong leaflets, terminal leaflets 7–10-lobed, margins serrate at least distally, lobe and leaflet apex acute or obtuse, lateral-veins 7–10 pairs, abaxial surface whitish-tomentose. Panicles 25–75-flowered, flat-topped or rounded, 4.5–10 cm diam.; peduncles white-villous. Pedicels white-villous. Flowers 10–15 mm diam.; hypanthium tomentose, hypanthium plus sepals 5–7.5 mm; sepals 1.5–4 mm, margins usually entire, rarely with inconspicuous glands; petals white, suborbiculate, broadly obovate, broadly ovate, or broadly elliptic, 5–7 mm; stamens 20; carpels 1/2 adnate to hypanthium, apex conic, styles 2 or 3, 2–3 mm. Infructescences glabrate to villous. Pomes red, globose to subglobose, 8–15 mm diam., shiny, not glaucous; sepals inconspicuous, incurved. Seeds redbrown, ovoid, 5–6 × 2 mm, asymmetric, slightly flattened. 2n = 68.


Phenology: Flowering spring; fruiting fall.
Habitat: Woods, rocky slopes, disturbed ground and edges near towns
Elevation: 0–1000 m

Distribution

V9 739-distribution-map.jpg

Introduced; N.B., Utah, Vt., Wash., n Europe

Discussion

Sorbus hybrida is considered an apomictic tetraploid producing fully fertile pollen and seed and subject to dispersal. An almost undistinguishable European taxon, S. ×thuringiaca (Ilse) Fritsch, often confused with S. hybrida, has been reported for New Hampshire and Vermont. Described as an unstable diploid hybrid between S. aria and S. aucuparia, S. ×thuringiaca has oblong leaves, 1–3(–5) pairs of free leaflets, 10–12(–13) pairs of lateral veins, and produces sterile pollen and relatively few viable seeds. Uncritical reports of escaped S. ×thuringiaca in North America should be considered doubtful; they probably refer to the more likely S. hybrida. The authors have not seen a specimen to document a report of S. hybrida from Montana.

Sorbus hybrida is placed in subg. Sorbus following J. J. Aldasoro et al. (2004), based on leaf division and pome characteristics, including the lack of tanniferous cells in parenchyma, lack of starch, and relatively small sclereid groups.

Selected References

None.

Lower Taxa

None.
... more about "Sorbus hybrida"
whitish-tomentose +
Peter F. Zika +  and Stéphane M. Bailleul +
Linnaeus +
compound +  and simple +
opposite +  and alternate +
not +  and clawed +
green +  and paler green +
7 cm70 mm <br />0.07 m <br /> (13 cm130 mm <br />0.13 m <br />) +
lobed +, oblong +, ovate +  and oblong-ovate +
5 cm50 mm <br />0.05 m <br /> (33 cm330 mm <br />0.33 m <br />) +
? (?) +  and ? (?) +
5cm +  and 11cm +
not glutinous +
brownish +  and purple +
white-villous +
0.4 cm4 mm <br />0.004 m <br /> (1 cm10 mm <br />0.01 m <br />) +
odd +  and simple +
divided +  and lobed +
tanniferous +
Oak-leaf mountain ash +
N.B. +, Utah +, Vt. +, Wash. +  and n Europe +
not +  and aggregated +
0–1000 m +
single-layered +
1 cm10 mm <br />0.01 m <br /> (1.5 cm15 mm <br />0.015 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 +
Woods, rocky slopes, disturbed ground and edges near towns +
rufous +  and whitish +
green +  and red +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
glabrate +  and villous +
crassinucellate +
deciduous +
obtuse +  and acute +
alternate +  and opposite +
papillose +
oblong +  and decurrent +
obtuse +  and acute +
entire +  and serrate +
toothed +, unlobed +  and lobed +
inferior +  and superior +
biseriate +  and clustered +
collateral +  and basal +
3 +  and 2 +
25-75-flowered +
4.5 cm45 mm <br />0.045 m <br /> (10 cm100 mm <br />0.1 m <br />) +
hairy +, glaucous +  and glabrous +
rounded +  and flat-topped +
white-villous +
white-villous +
0 (?) +  and 4 (?) +
free +  and distinct +
2 +  and 5 +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
Flowering spring +  and fruiting fall. +
adnate +, free +, connate +  and distinct +
0.8 cm8 mm <br />0.008 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
not glaucous +
globose +  and subglobose +
Sp. Pl. ed. +
not arillate +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
flattened;ovoid +
2 cm20 mm <br />0.02 m <br /> (?) +
persistent +
free +  and distinct +
inconspicuous +
triangular +  and ovate +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
Introduced +
free +  and distinct +
branched +  and simple +
ascending +  and erect +
persistent +  and deciduous +
short-adnate +  and free +
white-villous +
persistent +
distinct +
basal +, lateral +, subterminal +  and terminal +
elongate +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
glaucous +, hairy +  and glabrous +
Sorbus hybrida +
Sorbus sect. Sorbus +
species +
inconspicuous +
hairy +  and glabrous +