Rhododendron chaetomallum Balf. f. & Forr.

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An evergreen shrub up to 4 or 5 ft high; young shoots thickly clothed with twisted, bristly hairs. Leaves obovate, rounded at the end, tapered at the base, dark green and glabrous above except when quite young, velvety with a coat of tawny down beneath, 2 to 4 in. long, 1 to 134 in wide; stalk 15 in. long, stout, hairy like the shoot. Flowers in clusters of six to ten opening in March and April, on bristly stalks. Calyx red, up to 38 in. long, with five lobes unequal in shape and size. Corolla bell-shaped, 134 in. long and 212 in. wide, deep crimson, five-lobed. Stamens ten, up to 1 in. long, glabrous; anthers chocolate brown. Ovary densely woolly; style glabrous. Bot. Mag., n.s., t. 25 (s. Neriiflorum ss. Haematodes)

R. chaetomallum was discovered by Forrest in 1917-18 on the Mekong-Salween divide, N.W. Yunnan, growing in open thickets and on boulder-strewn slopes at 11,000 to 13,000 ft and was introduced by him at the same time under F. 14987, collected under the sacred mountain Ka-kar-po. From the Mekong it ranges westward across upper Burma and a variety has been discovered in the eastern Himalaya.

It is a variable species, distinguished from other members of the Haematodes subseries by the more or less bristly but not glandular young shoots and petioles, the lax, few-flowered truss, and the tomentose but not glandular ovary. Although a handsome species, it flowers too early for most gardens. The Award of Merit was given on April 7, 1959, to a form with Turkey Red flowers, raised at Exbury from Forrest 25601, collected on the Nmai (E. Irrawaddy)-Salween divide. The wild plants were said to have almost black-crimson flowers.

var. chamaephytum Cowan – Near var. hemigymnum but prostrate and almost glabrous. Described from Ludlow, Sherriff, and Taylor 3786, collected in the eastern Himalaya above Molo, near the border between Tibet and Assam.

var. glaucescens Tagg & Forr. – Leaves rather glaucous above.

var. hemigymnum Tagg & Forr. – Indumentum of leaf-undersurface thinner than normal, tending to wear off as the season advances. Forrest's 25605 is referred to this variety, but a plant raised from the corresponding seed-number at Tower Court, which received an Award of Merit in 1957, has the leaves densely brown-tomentose beneath.

var. xanthanthum Tagg & Forr. – Flowers creamy yellow flushed or striped with rose or rosy crimson; or striped and margined bright rose-pink on a yellowish base.

From the Supplement (Vol. V)

This is included in R. haematodes as a subspecies. The varieties mentioned are disposed of as follows:

[var. chamaephytum] – Possibly a natural hybrid between R. forrestii (or R. chamaethomsonii) and R. haematodes.

[var. glaucescens] – Included in R. haematodes subsp. chaetomallum.

[var. hemigymnum] – A natural hybrid between R. pocophorum and R. eclecteum – R. × hemigymnum (Tagg & Forr.) Chamberlain.

[var. xanthanthum] – Probably part of hybrid swarms involving R. catacosmum, R. citriniflorum and R. temenium.



Other species in the genus