An evergreen shrub up to 15 or 20 ft high; young shoots at first furnished with starry down and glands, afterwards glabrous. Leaves between oblong and oval, 6 to 12 in. long, 2 to 4 in. wide, dark green and loosely downy above and finally glabrous there, the undersurface at first covered with starry down and glands like the young shoots, much or all of which wears away leaving it pale and shining green; stalk up to 21⁄4 in. long. Flowers opening during July and August in trusses of twelve to sixteen, the main flower-stalk downy and glandular. Calyx 3⁄8 in. wide, with five broad shallow lobes; flower-stalk 1⁄2 to 1 in. long, bristly glandular. Corolla fleshy, funnel-shaped, 3 in. wide by 21⁄4 in. deep, rich crimson, downy outside, five-lobed, the lobes 1 in. wide; there are five darkly coloured pouches at the base. Stamens ten, crimson, up to 15⁄8 in. long, downy at the base. Ovary covered with tawny down; style 13⁄4 in. long, crimson, glandular over most of its length. Bot. Mag., t. 9271. (s. Irroratum ss. Parishii)
Native of eastern upper Burma; discovered in 1912 by Maung Kyaw, a collector in the Burmese Forest Service, after whom it is named. He found it near the Hpyepat bungalow, two stages short of Fort Htagaw, on the track from Myitkyina to Hpimaw on the Yunnan frontier. Seven years later Farrer and Cox collected seeds at the type-locality on their way back from the frontier area (Farrer 1444, Nov. 1919). But in the previous May Forrest had found a plant some 35 miles farther north at 9,000 ft, bearing last year's capsules, and collected seed, so the credit for introducing the species belongs to him (F. 17928, originally distributed as R. prophanthum).
R. kyawii is a magnificent species, but is seen to best advantage in the mildest parts or in a cool greenhouse. There is a plant at Eckford, Argyll, planted about 1930, 13 ft high and 40 ft in circumference (R.C.Y.B. 1968, p. 47). It is closely related to R. eriogynum, having the same starry down on various parts, the same glittering undersurface of the adult leaf, and the same habit of growing late in the season; but the foliage, flowers and the plant itself are larger.
R. agapetum Balf. f. & Ward – Very closely allied to R. kyawii and perhaps not specifically distinct. It was found by Kingdon Ward in 1914 growing on limestone cliffs below Hpimaw, on the Burma-Yunnan frontier, and was introduced by him in 1922 from the Taron Gorge, some 120 miles farther north. Forrest's 24680, of which the field specimen is identified as R. agapetum, was actually collected only a few miles from the type-locality of R. kyawii.
R. parishii C. B. Cl. – As the type of the Parishii subseries this species must be mentioned, though it is very tender and only suitable for cultivation in a large greenhouse. It was described in 1882 from a specimen collected by the Rev. C. Parrish at the southern end of the Dawna range, south-east of the Burmese port of Moulmein, at 6,500 ft. In 1912 it was rediscovered in the type-locality by J. H. Lace, Chief Conservator of Forests, Burma, who collected flower and fruit from which the species was more amply described in 1914 (Notes Roy. Bot. Gard. Edin., Vol. 8, p. 213). It is interesting that the affinity between R. parishii and R. kyawi, described in the same issue of the Notes, was not remarked on, perhaps because R. parisbii is very distinct from that species (and other members of the subseries) in its relatively short, broad leaves, only twice as long as wide. In leaf-indumentum and floral characters they are very similar.
From the Supplement (Vol. V)
R. agapetum becomes a synonym of this species.