Rhododendron thayerianum Rehd. & Wils.

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

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'Rhododendron thayerianum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-thayerianum/). Accessed 2020-10-29.

Genus

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.
bud
Immature shoot protected by scales that develops into leaves and/or flowers.
family
A group of genera more closely related to each other than to genera in other families. Names of families are identified by the suffix ‘-aceae’ (e.g. Myrtaceae) with a few traditional exceptions (e.g. Leguminosae).
glabrous
Lacking hairs smooth. glabrescent Becoming hairless.
glandular
Bearing glands.
oblanceolate
Inversely lanceolate; broadest towards apex.
raceme
Unbranched inflorescence with flowers produced laterally usually with a pedicel. racemose In form of raceme.
style
Generally an elongated structure arising from the ovary bearing the stigma at its tip.

References

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Credits

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

Recommended citation
'Rhododendron thayerianum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-thayerianum/). Accessed 2020-10-29.

Shrub, 3-4 m; bud scales persistent, at least on young shoots. Leaves stiff, 8-13 x 1.5-3 cm, narrowly oblanceolate, apex cuspidate, upper surface reticulate, lower surface with a dense one-layered fawn compacted indumentum composed of ramiform hairs. Flowers 10-15 in a truss, white tinged pink, lobes sometimes with a darker median line and purple flecks, funnel-shaped, nectar pouches lacking, 25-30 mm, ovary covered with rufous stalked glands, sometimes also with a rufous tomentum, style glandular to tip. Flowering June-July. Royal Horticultural Society (1997)

Distribution  China W Sichuan

Habitat c.2,700 m

RHS Hardiness Rating H5

Awards AM 1990 (Crown Estate Commissioners, Windsor); trusses 14-16-flowered, corolla white, faintly tinged pink when fully open, colour stronger in bud stage.

Conservation status Vulnerable (VU)

Taxonomic note The persistent bud scales and glandular style will distinguish this from the remaining species in the subsection. Royal Horticultural Society (1997)

An evergreen shrub up to 12 ft high in the wild; young shoots sticky and downy. Leaves crowded at the end of the shoot in a cluster of as many as twelve or more, leathery, oblanceolate, tapered abruptly to a finely pointed apex and gradually towards the stalk, which is 13 to 12 in. long; they are 212 to 8 in. long, 38 to 114 in. wide; bright green and ultimately glabrous above, covered beneath with a very close yellowish-brown felt. Flowers borne around midsummer, ten to sixteen in a terminal raceme the main-stalk of which is 1 to 112 in. long, glandular; the individual flower-stalks 112 to 2 in. long, slender, sticky with glands. Calyx cupped, with five glandular roundish lobes 16 in. long. Corolla five-lobed, funnel-shaped, about 114 in. long and a little more wide, opening pink, turning white, with bands of rosy red running lengthwise. Stamens normally ten, their white stalks downy on the lower half, about 1 in. long; anthers pale brown. Ovary and style very glandular. Bot. Mag., t. 8983. (s. Arboreum ss. Argy­rophyllum)

This species was discovered by Wilson in the Mupin area of W. Szechwan during his second expedition for the Arnold Arboretum in 1910. He found it in fruit, and the corollas were known only from withered remains until a plant raised from his seeds flowered at Caerhays in 1922. The rather loose trusses of flowers, which open in June and July, are delicately tinted and very charming. This is a very well-marked species, especially in its long narrow leaves which persist on the branches for four or five years; in the long slender flower-stalks which give the truss its loose appearance and a diameter of 6 in.; and in the sticky, glandular character of the young parts. It grows wild in woodlands. The Thayer family after whom it is named is an old and well-known one whose ancestral home is at Lancaster in Massachusetts. They generously supported the earlier Chinese expeditions.

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