Rhododendron glaucophyllum Rehd.

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

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'Rhododendron glaucophyllum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-glaucophyllum/). Accessed 2020-08-08.

Genus

Synonyms

  • Rhododendron glaucum Hook, f., not (Lam.) Sweet

Infraspecifics

Other species in genus

Glossary

calyx
(pl. calyces) Outer whorl of the perianth. Composed of several sepals.
corolla
The inner whorl of the perianth. Composed of free or united petals often showy.
style
Generally an elongated structure arising from the ovary bearing the stigma at its tip.
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.
bloom
Bluish or greyish waxy substance on leaves or fruits.
calyx
(pl. calyces) Outer whorl of the perianth. Composed of several sepals.
clone
Organism arising via vegetative or asexual reproduction.
glaucous
Grey-blue often from superficial layer of wax (bloom).
hybrid
Plant originating from the cross-fertilisation of genetically distinct individuals (e.g. two species or two subspecies).
ovate
Egg-shaped; broadest towards the stem.
variety
(var.) Taxonomic rank (varietas) grouping variants of a species with relatively minor differentiation in a few characters but occurring as recognisable populations. Often loosely used for rare minor variants more usefully ranked as forms.

References

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Credits

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

Recommended citation
'Rhododendron glaucophyllum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-glaucophyllum/). Accessed 2020-08-08.

Low shrub, to 1.5 m; shoots with a peeling reddish brown bark. Leaves (3.5-)4-6 x (1.3-)1.5-2.5 cm, narrowly elliptic to elliptic, lower surface with a glaucous papillate epidermis, the scales 1-3× their own diameter apart, unequal, the smaller golden, the larger brown. Pedicels scaly. Flowers (2-)4-6 per inflorescence; calyx lobes 6-9(-ll) mm, acuminate, with a tuft of hairs inside at the apex; corolla pink or white flushed pink, rarely white, sometimes also with flecks; campanulate to tubular-campanulate, (18-)20-27(-32) mm; stamens 10, regular; ovary scaly, style sharply deflexed or declinate, glabrous. Flowering April-May. Royal Horticultural Society (1997)

Distribution  BhutanChina S Tibet India Sikkim, Arunachal Pradesh

Habitat 2,750-3,650 m

RHS Hardiness Rating H5

Conservation status Data deficient (DD)

Taxonomic note Subsp. tubiforme has a more Easterly distribution than subsp. glaucophyllum. This species closely resembles R. luteiflorum (q.v.). White-flowered forms have been referred to var. album Davidian. Royal Horticultural Society (1997)

An evergreen shrub 3 to 6 ft high, of bushy habit, and usually wider than it is high; young branches, leaves, flower-stalks, and calyx covered with reddish-brown scurf or scales. Leaves oval or oblong, 1 to 3 in. long, 13 to 34 in. wide; margins recurved; upper surface dark dull green, lower one glaucous white or sometimes pale brown when young; stalk 18 to 13 in. long. The leaf when crushed has a strong, rather resinous odour. Flowers 34 to 114 in. wide, rosy red, produced during May in terminal clusters of usually five or six (sometimes eight to ten). Calyx large, with five ovate, pointed lobes, 13 in. long, scaly outside. Corolla bell-shaped, with five spreading, rounded lobes, slightly scaly outside; Stamens ten, downy at the base. Style straight or bent. Bot. Mag., t. 4721. (s. and ss. Glaucophyllum)

Native of the Himalaya from E. Nepal eastward at 10,000 to 12,000 ft; introduced by J. D. Hooker in 1850. It is quite hardy in a sheltered place, and pretty when well in bloom, though not showy. The hybrid ‘Rosy Bell’ derives from this species.

From the Supplement (Vol. V)

var. album Davidian – Flowers creamy white. This interesting variant was introduced from east Nepal by the University of North Wales Expedition (B.L. & M. 315). A clone deriving from this sending has been ‘Len Beer’, named after the leader of the expedition, who died in 1977 at the age of thirty-five (Rhododendrons 1977, pp. 69-70).

var. luteiflorum – See below, as R. luteiflorum.

var. tubiforme – Accepted as a variety in the Edinburgh revision, this has been promoted to species level by Mr Davidian and with good reason. In addition to being very distinct in floral characters it is geographically almost separate from R. glaucophyllum, its known occurrences being confined to eastern Bhutan, the Assam Himalaya and bordering Tibet. R. glaucophyllum proper ranges from Nepal to Bhutan. The type was collected by Kingdon Ward on the Manda La in the Assam Himalaya in 1935. The cultivated plants from the Ludlow and Sherriff introduction grow taller than R. glaucophyllum in gardens.

R. luteiflorum (Davidian) Cullen R. glaucophyllum var. luteiflorum Davidian – Kingdon Ward introduced this from The Triangle of northern Burma under two numbers – KW 21040 abnd KW 21556. Peter Cox reports that plants from the latter are somewhat more compact and hardy than those from the former (The Smaller Rhododendrons, p. 98).


subsp. glaucophyllum

Corolla campanulate; style sharply deflexed.

Distribution Nepal, India (Sikkim) Bhutan.

Habitat 3,050-3,350m.


subsp. tubiforme (Cowan & Davidian) D. G. Long

Synonyms
R. tubiforme (Cowan & Davidian) Davidian

Corolla tubular-campanulate; style declinate.

Distribution India (Arunachal Pradesh), Bhutan, China (S Tibet).

Habitat 2,750-3,650m.

Taxonomic note (R. tubiforme [Cowan & Davidian] Davidian)


var. luteiflorum Davidian

Flowers clear yellow. This interesting and attractive variety was discovered by Kingdon Ward and his wife in 1953 during their expedition to the northern part of the Triangle, a region of upper Burma lying between the two main branches of the upper Irrawaddy, the Nmai Hka and the Mali Hka. When he first saw it the flowers were over and he took it to be ordinary R. glaucophyllum. ‘My surprise, therefore, was great when the bright November sunshine so warmed the fat winter buds of this little plant that they blurted into brief flower, revealing golden corollas! It was a brighter and better R. brachyanthum’ (Return to the Irrawaddy, p. 172). It was introduced by him the same year and was described in 1960.A First Class Certificate was given in 1966 to a clone of the var. luteiflorum named ‘Glen Coy’, shown from the Brodick Castle Gardens, Isle of Arran (R.C.Y.B. 1967, Pl. 4).

var. tubiforme Cowan

Corolla tubular, style straight. Introduced by Ludlow and Sherriff from east Bhutan (L. & S. 2856).

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