Thamnocalamus spathiflorus (Trin.) Munro

[Arundinaria aristata Gamble]

Stems tufted, 8 to 12 ft or more high, 1⁄3 to 3⁄5 in. in diameter, at first glaucous green and white-scurfy, afterwards shining yellow; branches several at the joints, reddish. Stem-sheaths leaving a persistent cup-like base, straw-coloured, loose, with a ring of soft hairs at the base, sparsely stiffly hairy above, tipped with a short subulate blade. Leaf-blades in groups of two to three, oblong-lanceolate, 21⁄4 to 41⁄2 in. long, 2⁄5 to 2⁄3 in. wide, hairless or faintly hairy beneath, with three to five pairs of secondary nerves; leaf-sheaths bearing a few (six to eight) stiff purple bristles at the tip. Native of the N.E. Himalaya (Sikkim and Bhutan), where it grows at elevations of 9,000 to 10,000 ft. Suitable only for cultivation in the milder parts of the British Isles. It flowered in 1950–51.

[Arundinaria spathiflora Trin.]

An evergreen bamboo with erect, clustered stems that are 20 to 30 ft high in nature, yellowish brown, glabrous, 1⁄2 to 1 in. in diameter, much branched at the joints where, at the base of each, is a pale glaucous ring. Stem-sheaths rounded at the top except for an awl-shaped prolongation up to 2 in. long, not downy, ultimately straw-coloured, very smooth and glassy inside. Leaves 3 to 5 in. long, 1⁄4 to 1⁄2 in. wide, finely pointed, tapered to a short stalk at the base, of thin, fine texture. Secondary veins three to five each side the midrib; still finer longitudinal veins between these secondary ones are joined by minute but (as seen through a lens) conspicuous cross-veins, thereby giving the tesselated venation characteristic of all really hardy bamboos. One margin of the leaf is minutely toothed. Leaf-sheaths ribbed, fringed at the apex. Native of the N.W. Himalaya from 7,000 to 10,000 ft altitude; it flowered gregariously in 1882, from which seeding it was introduced. In general aspect of leaf and stem this bamboo most closely resembles Yushania anceps among hardy species, but its habit is tufted, whilst Y. anceps spreads so rapidly by its underground stems that it is liable to become a nuisance.T. spathiflorus is quite hardy at Kew, where it is about 8 ft high. In warmer localities it will probably get to be at least twice as high. It is a very elegant plant and may be grown in semi-shaded spots. In its natural state it covers large areas, often as undergrowth beneath deodars and other conifers, the whole area of plants flowering simultaneously and dying after the ripening of the seed.