Sorbus insignis (Hook. f.) Hedl.

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Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Recommended citation
'Sorbus insignis' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/sorbus/sorbus-insignis/). Accessed 2020-09-25.

Genus

Synonyms

  • Pyrus insignis Hook. f.
  • Sorbus harrowiana (Balf. f. & W.W. Sm.) Rehd.
  • P. harrowianus Balf. f. & W.W. Sm.

Glossary

herbarium
A collection of preserved plant specimens; also the building in which such specimens are housed.
inflorescence
Flower-bearing part of a plant; arrangement of flowers on the floral axis.
Tibet
Traditional English name for the formerly independent state known to its people as Bod now the Tibet (Xizang) Autonomous Region of the People’s Republic of China. The name Xizang is used in lists of Chinese provinces.
acute
Sharply pointed.
apex
(pl. apices) Tip. apical At the apex.
bud
Immature shoot protected by scales that develops into leaves and/or flowers.
convex
Having a rounded surface.
entire
With an unbroken margin.
glabrous
Lacking hairs smooth. glabrescent Becoming hairless.
glaucous
Grey-blue often from superficial layer of wax (bloom).
globose
globularSpherical or globe-shaped.
hybrid
Plant originating from the cross-fertilisation of genetically distinct individuals (e.g. two species or two subspecies).
included
(botanical) Contained within another part or organ.
indumentum
A covering of hairs or scales.
inflorescence
Flower-bearing part of a plant; arrangement of flowers on the floral axis.
lanceolate
Lance-shaped; broadest in middle tapering to point.
leaflet
Leaf-like segment of a compound leaf.
midrib
midveinCentral and principal vein in a leaf.
obtuse
Blunt.
ovoid
Egg-shaped solid.
petiole
Leaf stalk.
imparipinnate
Odd-pinnate; (of a compound leaf) with a central rachis and an uneven number of leaflets due to the presence of a terminal leaflet. (Cf. paripinnate.)
rachis
Central axis of an inflorescence cone or pinnate leaf.
retuse
Slightly notched at apex.
revolute
Rolled downwards at margin.
serrate
With saw-like teeth at edge. serrulate Minutely serrate.

References

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Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Recommended citation
'Sorbus insignis' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/sorbus/sorbus-insignis/). Accessed 2020-09-25.

A shrub, or more commonly a tree 25 to 40 ft high (said by Kingdon Ward to grow taller than this in the forests of N. Burma); young shoots stout, at first coated with brown and whitish hairs intermixed, later glabrous; winter-buds ovoid, 12 to 78 in. long, the outer scales glabrous except at the tip, the inner densely hairy. Stipules on sterile growths up to 1 in. wide and often persistent, toothed. Leaves up to 10 in. long with mostly two to five pairs of leaflets (but sometimes with a single pair and with up to seven or eight in KW 7746); rachis grooved, not winged; petiole with a wide, sheathing base, almost concealing the subtended bud. Leaflets leathery, oblong, mostly 2 to 5 in. long and 34 to 114 in. wide (but even larger on some Forrest specimens), more or less equal, but the basal pair sometimes smaller and more elliptic, apex subacute to obtuse or even retuse at the apex, oblique at the base, dark green and soon glabrous above, undersides (and rachis) at first coated with rusty and some whitish hairs, becoming glabrous except for a few hairs on the midrib, glaucous and papillose, margins often revolute and then apparently entire, but fine serrations evident when the leaflet is flat. Flowers small, creamy white, in convex clusters up to 6 in. wide; inflorescence-branches at first densely hairy, becoming glabrous or retaining a few white, spreading hairs, lenticellate. Petals roundish, about 18 in. wide. Styles two or three. Fruits globose, white, pink or purplish red, about 38 in. wide, in rather sparse clusters.

Native of the eastern Himalaya, east through upper Burma to S.W. Yunnan and bordering S.E. Tibet; described by Hooker in 1878 from Sikkim specimens but not introduced until Forrest sent seeds in 1912 from the Shweli-Salween divide near the border between Yunnan and Burma (F.9040); raised from this seed it flowered at Caerhays, Cornwall, in May 1924. Forrest later sent seed from other localities in the Burma-China borderland, and there was one sending by Farrer and Cox from the same area in 1921. Kingdon Ward sent seed in 1926 from the Seinghku valley, Burma, near the Assam frontier (KW 6851).

In its foliage, S. insignis is the most remarkable of the pinnate-leaved group of Sorbus, remote in aspect from the common rowan and suggesting some evergreen species from a subtropical rain-forest. The original Forrest introduction is very tender but a plant at Nymans in Sussex, probably from KW 6851, has survived there for about half-a-century.

The Yunnan-Burma forms of S. insignis have generally been known by the name S. harrowiana, described from a fruiting specimen collected by Forrest in 1912. Here, following Dr Hutchinson, this species is included in S. insignis. It is true that most specimens from Yunnan have fewer and larger leaflets than those of Sikkim (on some Forrest specimens they are 6 in. long and almost 2 in. wide), but the difference is not one on which to base two separate species, and is not constant.

More distinct from typical S. insignis (and from S. harrowiana) is the sorbus introduced by Kingdon Ward from Mt Japvo in the Naga Hills of Assam in 1927-8. This has long been grown as Sorbus sp. KW7746 (its field-number), but Dr Hutchinson, when working on Sorbus in the 1940s, identified it as S. insignis and his judgement has been upheld by other botanists. It agrees with S. insignis in most of its essential characters, but is certainly untypical in having up to seven or eight pairs of leaflets not more than 3 in. long, with brown hairs persisting on the midrib beneath. The deep pink fruits are borne in clusters of up to 100. It is hardier than the Forrest introductions.

S. ‘Bellona’. – So far a shrub of pyramidal habit about 10 ft high (1979). Winter-buds with rusty-hairy inner scales. Leaflets in three to five pairs, palish matt-green above, grey beneath, glabrous on both sides at maturity, narrowly oblong-obovate, toothed only in the upper one-third to one-half, 114 to 312 in. long and up to 1 in. wide. Fruits small, pale pinkish red, in trusses about 6 in. wide. Raised at Kew in 1956 from seeds received as S. harrowiana. Award of Merit September 7, 1971. It is evidently a hybrid of S. insignis but the other parent is uncertain.

S. ‘Ghose’. – A tree, ultimate height unknown. Young parts clad with a whitish or pale brown woolly indumentum that persists more sparsely on the undersides of the leaflets and in the inflorescence until the autumn. Leaflets in six to eight pairs, oblong or narrowly oblong-lanceolate, up to 212 in. long, serrate in the upper half, acute at the apex, oblique at the base, light matt-green above; petioles swollen at the base, but not sheathing the buds. Inflorescence about 6 in. wide, many-flowered, with stout main branches; stipules leafy, fan-shaped, toothed, persistent in some seasons. Fruits when nearly ripe dull crimson, eventually redder and glossy, 14 to 38 in. wide.

This interesting sorbus was raised by Messrs Hillier from seeds received from the Indian seedsman Ghose of Darjeeling. It seems to be intermediate between S. insignis and S. foliolosa (wallichii). It agrees in many respects with the description of S. arachnoidea Koehne, described from a specimen collected in Sikkim, and another from Chumbi, just across the border with Tibet, but these collections are not represented in the Kew Herbarium. Koehne likened his species to S. scalaris, with which ‘Ghose’ too has some affinity.

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