Rhododendron eudoxum Balf. f. & Forr.

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

Recommended citation
'Rhododendron eudoxum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-eudoxum/). Accessed 2020-10-26.

Genus

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.
inflorescence
Flower-bearing part of a plant; arrangement of flowers on the floral axis.
ovary
Lowest part of the carpel containing the ovules; later developing into the fruit.
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.
apex
(pl. apices) Tip. apical At the apex.
campanulate
Bell-shaped.
glabrous
Lacking hairs smooth. glabrescent Becoming hairless.
glandular
Bearing glands.
indumentum
A covering of hairs or scales.
mealy
Covered with coarse flour-like powder. (Cf. farinose.)
ovary
Lowest part of the carpel containing the ovules; later developing into the fruit.
style
Generally an elongated structure arising from the ovary bearing the stigma at its tip.
subspecies
(subsp.) Taxonomic rank for a group of organisms showing the principal characters of a species but with significant definable morphological differentiation. A subspecies occurs in populations that can occupy a distinct geographical range or habitat.
umbel
Inflorescence in which pedicels all arise from same point on peduncle. May be flat-topped (as in e.g. Umbelliferae) to spherical (as in e.g. Araliaceae). umbellate In form of umbel.
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 eudoxum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-eudoxum/). Accessed 2020-10-26.

Dwarf shrub, 0.3-1.2 m. Leaves 3.5-9 x 1-3 cm, elliptic, lower surface with a green epidermis and a thin discontinuous whitish to brown indumentum; petioles usually tomentose, sometimes also weakly setose. Flowers 2-6, in a tight truss; calyx 2-7 mm, cupular when well-developed; corolla not fleshy, pink to rose-carmine, tubular-campanulate to campanulate, 25-40 mm; ovary predominantly glandular to predominantly tomentose, abruptly contracted into the glabrous style. Flowering April-May. Royal Horticultural Society (1997)

Distribution  China border between Tibet & Yunnan

Habitat 3,350-4,250 m

RHS Hardiness Rating H5

Conservation status Least concern (LC)

An evergreen shrub up to 6 ft high in the wild. Leaves thinly leathery, oblong-elliptic to oblong-obovate, rounded at the apex, up to 278 in. long and 1 in. wide, glabrous above when mature, underside clad with a ‘very thin discontinuous mealy indumentum composed of branched or star-like hairs … scattered over the undersurface of the leaf. At the same time the undersurface of the leaf is very minutely papillate and has a greenish brown appearance’ (Cowan, Notes R.B.G. Edin., Vol. 20, p. 77). Inflorescence a terminal umbel of three to six flowers, opening in April or May (later in some forms). Calyx fleshy at the base, up to 14 in. deep. Corolla tubular-campanulate, 112 in. long, crimson or pink. Stamens downy at the base. Ovary tomentose and glandular; style glabrous. (s. Neriiflorum ss. Sanguineum)

R. eudoxum is a native of N.W. Yunnan and bordering parts of Tibet (Tsarong) on the Mekong-Salween and Salween-Irrawaddy divides and was introduced by Forrest. It received an Award of Merit when shown by E. H. M. and P. A. Cox on April 26, 1960 (a form with flowers of the shade of pink known as Solferino Purple, with a deeper crimson tinge at the base).

subsp. brunneifolium (Balf. f. & Forr.) Cowan R. brunneifolium Balf. f. & Forr. – Differing from the typical state mainly in having the ovary eglandular.

From the Supplement (Vol. V)

The Edinburgh revision recognises only three varieties, not subspecies, here:

var. eudoxum. – The typical variety with a mainly glandular ovary.

var. brunneifolium (Balf.f. & Forr.) Chamberlain – Leaves 234 to 312 in. long; indumentum brownish. Ovary mainly tomentose.

var. mesopolium (Balf.f. & Forr.) Chamberlain – Leaves 138 to 312 in. long; indumentum whitish. Ovary mainly tomentose.

For synonymy, see Rev. 2, pp. 401-3.


R fulvastrum Balf. f. & Forr

Leaves with a thin indumentum beneath (not continuous and plastered as in R. sanguineum), but differing from R. eudoxum in that the indumentum is cobwebby, not mealy as in that species, and is made up of scattered, long-branched hairs (Cowan). Ovary tomentose, eglandular. Flowers typically pale yellow, but rose, pink, or yellowish red in subsp. meso-polium (Balf. f. & Forr.) Cowan.

var. brunneifolium (Balf.f. & Forrest) D.F.Chamb.

Synonyms
R. brunneifolium Balf.f. & Forrest

Ovary predominantly tomentose; leaves 7-9cm, indumentum brownish; corolla c.40mm. Royal Horticultural Society (1997)


var. eudoxum

Synonyms
R. trichomiscum Balf.f. & Forrest
R. trichophlebium Balf.f. & Forrest

Ovary predominantly glandular. Royal Horticultural Society (1997)

Awards
AM 1960 (E.H.M. & P.A. Cox, Glendoick, Perth); flowers Solferino Purple with a basal crimson fringe.


var. mesopolium (Balf.f. & Forrest) D.F.Chamb.

Synonyms
R. epipastum Balf.f. & Forrest

Ovary predominantly tomentose; leaves 3.5-7 cm, indumentum whitish; corolla 30-35 mm. Royal Horticultural Society (1997)

A variable species that may have arisen as a hybrid of R. sanguineum. It is also allied to R. temenium (q.v.). Royal Horticultural Society (1997)

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