Rhododendron hyperythrum Hayata

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

Recommended citation
'Rhododendron hyperythrum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-hyperythrum/). Accessed 2020-06-03.

Genus

Synonyms

  • R. rubropunctatum Hayata, not Lévl. & Van.

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.
acute
Sharply pointed.
apex
(pl. apices) Tip. apical At the apex.
appressed
Lying flat against an object.
campanulate
Bell-shaped.
ciliate
Fringed with long hairs.
glabrous
Lacking hairs smooth. glabrescent Becoming hairless.
glandular
Bearing glands.
included
(botanical) Contained within another part or organ.
midrib
midveinCentral and principal vein in a leaf.
oblanceolate
Inversely lanceolate; broadest towards apex.
petiole
Leaf stalk.
style
Generally an elongated structure arising from the ovary bearing the stigma at its tip.
tomentum
Dense layer of soft hairs. tomentose With tomentum.
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.

References

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Credits

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

Recommended citation
'Rhododendron hyperythrum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-hyperythrum/). Accessed 2020-06-03.

Shrub, to 2.5 m; young shoots and petioles with a floccose indumentum though soon glabrescent; bud scales deciduous. Leaves 8-12 x 2.5-3.5 cm, elliptic, apex more or less cuspidate, upper surface glabrous, lower surface with persistent punctate hair bases, otherwise glabrous, or with some persistent dendroid hairs, especially towards base and on midrib. Flowers c.10, in a lax truss; calyx c.3 mm; corolla white, with reddish flecks, funnel-campanulate, without nectar pouches, 35-45 mm; ovary densely glandular, style glandular below. Flowering April-May. Royal Horticultural Society (1997)

Distribution  Taiwan (China)

Habitat 1,000-1,300 m

RHS Hardiness Rating H7

Awards AM 1976 (Capt. c. Ingram, Benenden, Kent) to a clone 'Omo'; flowers white.

Conservation status Data deficient (DD)

Taxonomic note R. hyperythrum is a distinctive species without close allies. Royal Horticultural Society (1997)

A dense evergreen shrub usually not more than 6 ft high in cultivation, but twice that in width; branchlets stout, glabrous. Leaves leathery, oblong-elliptic or oblong-oblanceolate, acute and mucronate at the apex, margins strongly recurved (at least in the cultivated form), 312 to 6 in. long, 1 to 134 in. wide, dark green and glabrous above, with an impressed midrib, undersurface dotted with minute punctulations, which are more evident on dried specimens than on live material, glabrous, but the prominent midrib at first covered with a floccose tomentum; petiole at first hairy like the midrib, up to 1 in. long. Inflorescence a racemose umbel of about ten flowers opening in April or May; pedicels up to 134 in. long, floccose. Calyx small, the lobes triangular, ciliate, about 18 in. long. Corolla five-lobed, funnel-campanulate, about 134 in. long and wide, pink or white and more or less speckled in wild plants, pure white and almost unspeckled in the cultivated form. Filaments of stamens downy at the base. Ovary coated with short, spreading or appressed hairs, scarcely glandular; style hairy at the base. Bot. Mag., n.s., t. 109. (s. Ponticum ss. Caucasicum)

Native of Formosa, where it is said to be very local. It was described from a specimen collected on the central ranges, while the type of R. rubropunctatum was collected at the northern extremity of the island, where the species occurs north and east of Taipei. It was described by Hayata in 1913 and introduced by Lionel de Rothschild to Exbury in the 1930s. It is of uncertain taxonomic position, but seems to be very distinct from R. morii, in which it was included by Kanehira. It is at present placed in the Caucasicum subseries of s. Ponticum. R. hyperythrum is perfectly hardy, needs only light shade and a sheltered position, grows quickly and flowers when quite young. In the form usually seen in cultivation the flowers are pure white and almost unmarked, in this respect differing from most wild plants (see the note by K. Wada in Rhododendrons 1972, pp. 33-4). R. hyperythrum is one of the best species for a small garden, being of neat habit, with striking foliage and beautiful flowers.


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