Plant. Wilson. I. 529 (1913); Millais, Rhododendrons, 203 (1917); Bean, Trees & Shrubs Hardy in Brit. Isles, Ed. 3, II. 366 (1921); Tagg in [Rhododendron Soc.], Species of Rhododendron, 147 (1930). Syn. R. Brettii Hemsl. & Wils. in Kew Bull. 1910, p. 106. Rhododendron longesquamatum was so named by C. K. Schneider in 1909 on account of the remarkably dense indumentum of long branched hairs which covers the branch- lets and the midrib on the lower surface of the leaves. But it is not only on this very distinct characteristic that the species may be at once recognised, for a microscopical examination of the lower surface of the leaves reveals the presence of very peculiar scattered pustule-like glands, a very rare feature in Rhododendron leaves, except those which are truly lepidote. R. longesquamatum shares this dual character with R. Edgeworthii, but otherwise, of course, there is no further resemblance between the two species. From an evolutionary point of view, however, the two species are very interesting as showing, perhaps, the beginning of the peltate scales characteristic of the lepidote groups, for the peltate scale is but a higher type of the branched hairs which are also found on the leaves of the two species mentioned. A year or so after Schneider, Hemsley and E. H. Wilson also gave a name to the species, calling it R. Brettii, after Mr. H. J. Brett, of the Chinese Consular Service, who was stationed at Chengtu, Szechwan in 1904. Both descriptions were based on Wilson's number 3973 collected at Tatsienlu in July, 1903. In subsequent years Wilson gathered further specimens in various localities in Szechwan, at altitudes of 2700-3000 metres, where it flowers as late as July, but in cultivation in this country towards the end of June. It should be noted, however, that in Plantae Wilsonianae,.

R. Brettii Hemsl. & Wils. in Kew Bull. 1910