Rhododendron dichroanthum Diels

TSO logo

Sponsor

Kindly sponsored by Peter Norris, enabling the use of The Rhododendron Handbook 1998

Credits

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

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

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.
ovary
Lowest part of the carpel containing the ovules; later developing into the fruit.
apex
(pl. apices) Tip. apical At the apex.
corolla
The inner whorl of the perianth. Composed of free or united petals often showy.
glabrous
Lacking hairs smooth. glabrescent Becoming hairless.
glaucous
Grey-blue often from superficial layer of wax (bloom).
mucro
Short straight point. mucronate Bearing a mucro.
oblanceolate
Inversely lanceolate; broadest towards apex.
ovary
Lowest part of the carpel containing the ovules; later developing into the fruit.
ovate
Egg-shaped; broadest towards the stem.
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.

References

There are currently no active references in this article.

Credits

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

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

Dwarf shrub, 0.3-2.3 m. Leaves 4-9.5 x 2-4 cm, oblanceolate to elliptic, lower surface with a continuous white to fawn, more or less loose to compacted indumentum composed of rosulate hairs; petioles covered with a white floccose indumentum. Flowers 3-6, in a tight truss; calyx coloured, 3-15 mm, cupular when well-developed; corolla fleshy, usually orange-red, occasionally yellow flushed red or carmine, tubular-campanulate, with nectar pouches, 35-50 mm; ovary rufous-tomentose, with or without stalked glands, abruptly tapering into the glabrous style. Flowering May-June. Royal Horticultural Society (1997)

Distribution  Myanmar NE China W Yunnan

Habitat 2,750-4,400 m

RHS Hardiness Rating H5

Conservation status Vulnerable (VU)

An evergreen shrub 2 to 5 ft high, of stiff close growth; young shoots at first white with a close down, grey the second season. Leaves obovate to oblance­olate, tapered abruptly at the apex to a short mucro, always more or less wedge-shaped at the base, 2 to 4 in. long, 34 to 112 in. wide, dark green and glabrous above, covered beneath with a glaucous white, thin, scurfy down; stalk 14 to 12 in. long. Flowers opening in May, six to eight in a terminal truss; flower-stalk 12 to 1 in. long, white with down. Calyx very variable in the size and shape of the lobes; 16 to 1 in. long and awl-shaped to roundish ovate, approximating the corolla in colour. Corolla fleshy, elongated-bell-shaped, 134 in. long, scarcely so wide; the colour is variable in different plants and may be of various shades of orange, often more or less suffused with pink. Stamens ten, scarcely as long as the corolla, slightly downy at the base. Ovary clothed with white down and fascicled hairs; style glabrous. Bot. Mag., t. 8815. (s. Neriiflorum ss. Sanguineum)

Native of the Tali range, Yunnan, China; discovered by Forrest in 1906 and introduced to cultivation by him. His F.11597, with deep orange flowers, is perhaps the most desirable form, but others are very attractive. Forrest describes some shades as ‘creamy rose’ or ‘yellowish rose’. In its best forms this is one of the most attractive members of the series and quite hardy.

subsp. apodectum (Balf. f. & W. W. Sm.) Cowan R. apodectum Balf. f. & W. W. Sm.; R. jangtzowense Balf. f. & Forr.; R. liratum Balf. f. & Forr. – Distinguished from typical R. dichroanthum by its very leathery, round-based leaves. It appears to be confined to the Shweli-Salween divide, and was introduced by Forrest in 1913. Bot. Mag., t. 9014.

subsp. herpesticum (Balf. f. & Ward) Cowan R. herpesticum Balf. f. & Ward – -This is easily distinguished from typical R. dichroanthum and subsp. apodectum by the flower-stalks, calyces, and ovaries being furnished with glands. Also the leaves are more like those of R. sanguineum in size and shape, being oblanceolate or oblong-elliptic, up to 3 in. long and 118 in wide. The shoots are sometimes bristly. This subspecies was discovered by Kingdon Ward in July 1914 in upper Burma, on the northern slope of Imaw Bum, a mountain just over 13,000 ft high on the divide between the Salween and the upper Irrawaddy (Nmai Hka), forming tanglements about 1 ft high. It is fairly widely distributed in the borderland between Yunnan and Burma, and was sent many times by Forrest, who introduced it.

subsp. scyphocalyx (Balf. f. & Forr.) Cowan R. scyphocalyx Balf. f. & Forr. – This does not really differ from the subsp. herpesticum in any character of genuine taxonomic importance, but typically it is four or five times as tall and the leaves are larger and thinner. But intermediate forms occur. It was discovered by Forrest in 1919 about twenty miles to the west of the type-locality of subsp. herpesticum and has the same distribution. He sent seeds many times from 1919 onward and it is also in cultivation from Farrer 1024, this too collected in 1919. The flowering-time of both subspecies is mostly May. The colour range of wild plants is extraordinarily wide – rose-orange, yellowish crimson, coppery yellow, fiery bronze, flame, orange, cinnabar-scarlet, very dark yellowish crimson, etc. Unfortunately, cultivated plants often bear flowers the colour of marmalade or mustard-pickle.

subsp. septentrionale Cowan R. scyphocalyx var. septentrionale Tagg MS – Leaves as in subsp. herpesticum, but ovary without glands. Flowers yellow or yellow flushed rose. Introduced by Forrest. He found it originally about 50 miles to the north of the type-locality of subsp. scyphocalyx, whence the epithet septentrionale.

From the Supplement (Vol. V)

Dr Cowan’s treatment of this species is accepted in the Edinburgh revision, except that subsp. herpesticum is submerged in subsp. scyphocalyx (Rev. 2, p. 394).


subsp. apodectum (Balf.f. & W.W.Sm.) Cowan

Leaves 1.9-2.5× as long as broad, indumentum silvery to fawn; ovary lacking glands; young shoots not setose.

Distribution NE Burma, China (W Yunnan).


subsp. dichroanthum

Leaves 2.5-3× as long as broad, indumentum silvery; ovary lacking glands; young shoots not setose.

Distribution China (W Yunnan).

Awards AM 1923 (Lady Aberconway and Hon. H.D. Mclaren, Bodnant); flowers brick red.


subsp. scyphocalyx (Balf.f.& Forrest) Cowan

Synonyms
R. herpesticum Balf.f. & Kingdon-Ward
R. scyphocalyx Balf.f. & Forrest

Leaves 1.9-2.7× as long as broad, indumentum fawn; ovary stalked-glandular; young shoots often glandular-setose.

Distribution NE Burma, China (W Yunnan).

Taxonomic note (R. scyphocalyx Balf.f. & Forrest, & incl. R. herpesticum Balf.f. & Kingdon-Ward)


subsp. septentrionale Cowan

Synonyms
R. scyphocalyx Balf.f. & Forrest var. septentrionale Davidian

Leaves 3-3.3× as long as broad, indumentum whitish to fawn; ovary with or without stalked glands; young shoots not setose.

Taxonomic note (R. scyphocalyx Balf.f & Forrest var. septentrionale Davidian)

Some of the variation of this species is correlated with geographical distribution. It is closely allied to R. sanguineum.

Feedback

A site produced by the International Dendrology Society.

For copyright and licence information, see the Licence page.

To contact the editors: info@treesandshrubsonline.org.