Rhododendron megacalyx Balf. f. & Ward

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

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'Rhododendron megacalyx' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-megacalyx/). Accessed 2020-04-02.

Genus

Other species in genus

Glossary

calyx
(pl. calyces) Outer whorl of the perianth. Composed of several sepals.
capsule
Dry dehiscent fruit; formed from syncarpous ovary.
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.
bloom
Bluish or greyish waxy substance on leaves or fruits.
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.
glabrous
Lacking hairs smooth. glabrescent Becoming hairless.
ovate
Egg-shaped; broadest towards the stem.
style
Generally an elongated structure arising from the ovary bearing the stigma at its tip.

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Credits

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

Recommended citation
'Rhododendron megacalyx' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-megacalyx/). Accessed 2020-04-02.

Shrub, 1-3.5 m; young shoots not setose. Leaves 10-16 x 4.5-7.5 mm, elliptic to obovate, apex rounded, margin not ciliate, upper surface usually bullate with midrib impressed, lower surface brownish, with unequal more or less touching golden or brownish scales, the smaller of which are rimless. Flowers 2-6, in a loose terminal inflorescence, strongly scented; calyx lobes 22-30 mm, whitish-pruinose, becoming papery in fruit, glabrous and lacking scales; corolla white or cream, rarely flushed pinkish purple, funnel-campanulate, with an oblique mouth, 65-95 mm, outer surface sparsely scaly; stamens 10; ovary densely scaly, tapering into the style that is scaly at base. Flowering April-June. Royal Horticultural Society (1997)

Distribution  Myanmar NE China Yunnan, SE Tibet India Arunachal Pradesh

Habitat 2,000-3,350 m

RHS Hardiness Rating H4

Awards AM 1937 (Vice Adm. A.W. Heneage-Vivian, Clyne Castle, Swansea); flowers pure white.

Conservation status Least concern (LC)

Taxonomic note This is a very distinctive species. Royal Horticultural Society (1997)

An evergreen shrub up to 10 ft or 15 ft high in the wild, described by Ward as of ‘tall, loosely knit’ habit. Leaves oblong-oval, often inclined to obovate, mostly rounded at the apex, 4 to 6 in. long, 1 to 3 in. wide, strongly veined, dull light green and glabrous above, densely furnished with sunken, yellow-brown scales beneath; stalk 12 to 34 in. long, with a shallow groove on the upper side. Flowers drooping, opening April to early June in loose clusters of three to five, with a nutmeg-like fragrance. Pedicels stout, up to 114 in. long, glabrous. Calyx very large, bell-shaped, 34 to 118 in, long, with five deep, rounded ovate lobes, glabrous and without scales. Corolla funnel-shaped, 4 in. long and as much wide, pure white or flushed with pinkish purple, stained with pale yellow at the base inside. Stamens ten, shorter than the corolla, downy at the lower part. Ovary and base of style scaly. Capsule very short, about 34 in. long, surrounded by the persistent calyx. Bot. Mag., t. 9326. (s. Maddenii ss. Megacalyx)

Native of the borderland between China and upper Burma westward across the upper Irrawaddy to the region of the Tsangpo bend, at the eastern end of the Himalaya; discovered by Kingdon Ward in 1914 in the valley of the Nmai Hka, Burma, at 7,000-8,000 ft; introduced by Forrest in 1917 from the Shweli-Salween divide, about 20 miles south of the type-locality. Two years later Farrer and Cox collected seeds a few miles north of the original locality and at the same altitude. ‘It is a tall shrub, or small spindly tree, with large, loose heads of blossom, passing over by the middle of May. The long stout pedicels are clothed in a sort of blue bloom, the big conspicuous calyx is crimson and pink and green. The flowers are of enormous size, pure white, flushed with pink, orange-anthered, and limp in texture, so as to suggest some floppy, snow-white flowered Gloxinia. Add to all this an intense fragrance of clove, and you may imagine with what acclamations I gathered in this new recruit …’ (Farrer, Gard. Chron., Vol. 66 (1919), p. 161). The fragrance is usually likened to that of nutmeg, whence Kingdon Ward’s nickname for the species – ”Nutmegacalyx”.

R. megacalyx is too tender to be grown outdoors in the London area, but succeeds in some gardens of the Atlantic zone. It received an Award of Merit when shown by Adm. Heneage-Vivian of Clyne Park, Swansea, on June 7, 1937.


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