Rhododendron primuliflorum Bur. & Franch.

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Credits

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

Recommended citation
'Rhododendron primuliflorum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-primuliflorum/). Accessed 2024-03-18.

Genus

Synonyms

  • Rhododendron fragrans (Adams) Maxim., not Paxt.
  • Azalea fragrans Adams
  • Rhododendron adamsii Rehd.
  • Rhododendron clivicola Balf. f. & W. W. Sm.
  • Rhododendron cremnophilum Balf. f.
  • Rhododendron gymnomiscum Balf. f. & Ward
  • Rhododendron praeclarum Balf. f. & Farrer
  • Rhododendron tsarongense Balf. f. & Forr.

Infraspecifics

Other taxa 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.
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.
bud
Immature shoot protected by scales that develops into leaves and/or flowers.
corolla
The inner whorl of the perianth. Composed of free or united petals often showy.
disjunct
Discontinuous; (of a distribution pattern) the range is split into two or more distinct areas.
glabrous
Lacking hairs smooth. glabrescent Becoming hairless.
mucro
Short straight point. mucronate Bearing a mucro.
stigma
(in a flower) The part of the carpel that receives pollen and on which it germinates. May be at the tip of a short or long style or may be reduced to a stigmatic surface at the apex of the ovary.
style
Generally an elongated structure arising from the ovary bearing the stigma at its tip.

Credits

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

Recommended citation
'Rhododendron primuliflorum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-primuliflorum/). Accessed 2024-03-18.

Small shrub, to 1(–1.5) m; leaf bud-scales quickly deciduous. Leaves 1.1–3.5 × 0.5–1(–1.5) cm, narrowly elliptic to elliptic, apex rounded or tapered, lower surface with 2–3 tiers of dense overlapping scales, the lowest tier, golden yellow, the upper tiers pale brown to brown. Flowers several, in a dense racemose umbel; calyx lobes 2.5–6 mm; corolla white flushed pink to pink, often yellowish orange towards base of tube, hypocrateriform, tube 6–12 mm, outer surface usually glabrous, more rarely sparsely pilose or scaly, densely pilose within at throat; stamens 5(–6); capsule scaly. Flowering April-May. Royal Horticultural Society (1997)

Distribution  China N Yunnan, S Tibet, SW Sichuan

Habitat 3,350–4,600 m

RHS Hardiness Rating H5

Awards AM 1980 (P.A. Cox, Glendoick) to a clone 'Doker-la', as R. primuliflorum var. cephalanthoides; truss compact, 10-12-flowered, corolla red-purple, paling to near white at rim.

Conservation status Least concern (LC)

Taxonomic note This widespread species resembles R. cephalanthum but it may be distingished by the deciduous leaf bud scales, etc. Royal Horticultural Society (1997)

An evergreen strongly aromatic shrub 1 to 4 ft high; young shoots densely covered with scales; leaf-bud scales soon falling. Leaves oval or inclined to oblong, tapered about equally to both ends, but with a mucro at the tip, 12 to 1 in. long, 14 to 12 in. wide, dark, rather bright green and somewhat scaly above, thickly covered beneath with reddish scurf; leaf-stalk 18 in. long. Flowers in a many-flowered, compact, hemispherical truss opening in spring. Calyx 14 in. long, five-lobed, the lobes unequal in length, sometimes fringed with hairs, finely downy outside. Corolla white, pale yellow, or rose, 34 in. long, tubular, spreading above into five rounded lobes, downy outside, hairy in the tube. Stamens five, enclosed in the tube, finely downy at the base or glabrous. Ovary scaly, dome-shaped; style very short, stout, glabrous, with a broad flat stigma. (s. Anthopogon)

R. primuliflorum, as interpreted by Cowan and Davidian, is one of the most wide-ranging of rhododendron species, with a disjunct distribution. Its northern area lies in Russia, from E. Siberia east to the Sea of Okhotsk, and in N. Mongolia. South of the Gobi desert its area stretches from the Chinese province of Kansu southward to N.W. Yunnan and westward to E. and S.E. Tibet. It is reported that fossilised peat soils lie beneath the sands of the Gobi desert so the separation of the species into two areas may be of comparatively recent date.

This species was described, as Azalea fragrans, from a specimen collected in Russia near the mouth of the river Lena, and later as Azalea pallida, also from Russia. But neither of these names is valid in Rhododendron, and it was not until 1921 that Rehder provided the name R. adamsii for the Russian plants. But in the meantime Franchet had given the name R. primulaeflorum to a specimen collected in Tibet between Lhasa and Batang and that is therefore the valid name for the species as a whole.

R. primuliflorum (the name is so spelt under modern rules) is represented in gardens by plants raised from seeds collected in W. China and bordering parts of Tibet, where it occurs at altitudes of up to 14,000 ft. It is closely allied to R. cephalanthum but in that species the stamens are sometimes up to eight in number and the bud-scales are persistent. It is rare in cultivation.

From the Supplement (Vol. V)

The var. cephalanthoides is not recognised in the Edinburgh revision, plants with downy corolla tubes being considered as part of the normal variation of the species.

cv. ‘Doker La. – Flowers pink, in April or early May, freely borne. Award of Merit 1980 when exhibited by Glendoick Nurseries.

† R. Adamsii Rehd. R. fragrans (Adams) Maxim. (1870), not R. fragrans Paxton (1843); Azalea fragrans Adams – This species was sunk in R. primuliflorum by Cowan and Davidian and is restored to its original status by Dr Cullen, under the name R. fragrans (Rev. 1, p. 167). It is responsible for the northern part of the range of R. primuliflorum, as given on page 746, being a native of the region from eastern Siberia to the Sea of Ohotsk, and of Mongolia.


var. cephalanthoides (Balf. f. & Forr.) Cowan & Davidian

Synonyms
R. cephalanthoides Balf. f. & Forr

Corolla-tube densely downy outside.