Rhododendron macabeanum Watt ex Balf. f.

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

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'Rhododendron macabeanum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-macabeanum/). Accessed 2020-10-26.

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.
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.
apex
(pl. apices) Tip. apical At the apex.
campanulate
Bell-shaped.
corolla
The inner whorl of the perianth. Composed of free or united petals often showy.
glabrous
Lacking hairs smooth. glabrescent Becoming hairless.
included
(botanical) Contained within another part or organ.
indumentum
A covering of hairs or scales.
midrib
midveinCentral and principal vein in a leaf.
obtuse
Blunt.
petiole
Leaf stalk.
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.
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.
variety
(var.) Taxonomic rank (varietas) grouping variants of a species with relatively minor differentiation in a few characters but occurring as recognisable populations. Often loosely used for rare minor variants more usefully ranked as forms.

References

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Credits

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

Recommended citation
'Rhododendron macabeanum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhododendron/rhododendron-macabeanum/). Accessed 2020-10-26.

Tree, to 15 m; bark rough. Leaves 14-25 x 9-18.5 cm, broadly ovate to broadly elliptic, apex rounded, often apiculate, lower surface with a dense two-layered indumentum, the upper layer lanate-tomentose, composed of rosulate and ramiform hairs, the lower compacted; petioles terete. Flowers 15-25, in a dense truss, 8-lobed, lemon yellow, with a purple blotch in the throat, tubular-to narrowly funnel-campanulate, with nectar pouches, c.50 mm; stamens 16; ovary densely rufous-tomentose. Flowering March-May. Royal Horticultural Society (1997)

Distribution  India Manipur, Nagaland

Habitat 2,500-3,000 m

RHS Hardiness Rating H4

Awards AM 1937 and FCC 1938 (Lt Col E.H.W. Bolitho, Trengwainton, Cornwall); flowers yellowish white, with a bright red stigma. AGM 1993

Conservation status Endangered (EN)

Taxonomic note In cultivation the hybrids with R. sinogrande are often difficult to distinguish from this species, but usually can be separated by the floccose leaf indumentum that tends to rub off. Royal Horticultural Society (1997)

A large evergreen shrubby tree in the wild, attaining a height of 40 to 50 ft; young stems coated with a woolly greyish tomentum. Leaves thick and leathery, clustered at the ends of the shoots, oblong-elliptic to broadly oval, up to 1 ft long, 6 to 9 in. wide, rounded and mucronate at the apex, narrowed or obtuse at the base, dark green above, undersurface whitish or greyish white, at first woolly from a coating of long-branched hairs which later fall away, leaving a suede-like indumentum of rosulate hairs; midrib and lateral veins prominent beneath; petiole stout, about 1 in. long, tomentose. Inflorescence a dense umbel of up to thirty flowers, opening in March or April; pedicels about 78 in. long, tomentose. Calyx rim-like. Corolla pale sulphur yellow to deep yellow, some­times ivory-white, tubular-campanulate, pouched at the base, the upper pouches purple inside, almost 3 in. long, 2 to 214 in. wide, eight-lobed. Stamens sixteen, included in the corolla, with glabrous filaments. Ovary sixteen-chambered, tomentose; style glabrous, with a large crimson or pink stigma. Bot. Mag., n.s., t. 187.

(s. Grande)

Native of Assam in the Naga Hills and Manipur. It was discovered by Sir George Watt on Mt Japvo at 8,000 to 9,500 ft on March 9, 1882; a few weeks later he collected it again on the summit at 9,800 ft, where, as in neighbouring mountains at about the same altitude, it forms dwarf forests. In addition to making field notes, Sir George Watt drew up a description of this rhododendron, and tentatively gave it the status of a variety of R. falconeri. He named it after Mr M’Cabe, Deputy Commissioner for the Naga Hills, who helped him during his visit. But Watt’s account lay in manuscript until 1920, when Sir Isaac Bayley Balfour used it, and the specimens he collected, to make a formal description of this rhododendron, as a new species. Seven years later, Kingdon Ward collected seeds from the Japvo stand, and from these all the older plants in gardens are derived (KW 7724). He again gathered seeds in March 1935, this time from farther east, on a ridge at 9,000 ft below Mt Sarameti (KW 11175).

R. macabeanum is hardy in woodland near London and thrives and flowers beautifully in several gardens, notably at Nymans in Sussex. But it grows faster and attains its greatest size in the milder and rainier parts, where plants from the original introduction are now around 25 ft in height. At Kew, the climate is too dry for it, but it grows well at Edinburgh, where there is a fine specimen in the Rhododendron Walk. The yellow of its flowers varies much in depth, even in the plants from Kingdon Ward’s original collection. At Trengwainton, where Sir Edward Bolitho raised many plants from KW 7724, some are deep yellow and among the finest in the country. But the trusses shown by him in 1937 and 1938 were of pale yellow flowers, though still fine enough for the species to receive the Award of Merit on the first occasion and a First Class Certificate on the second. The famous plant at Trewithen, Cornwall, was a gift from Sir Edward Bolitho to George Johnstone and is one of the original seedlings. This has flowers of a very deep yellow and measures 23 ft in height and 35 ft in width (1974). It is portrayed in R.C.Y.B. 1962, fig. 14.

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