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Tim Baxter & Hugh A. McAllister (2021)
Recommended citation
Baxter, T. & McAllister, H.A. (2021), 'Alnus subcordata' from the website Trees and Shrubs Online (treesandshrubsonline.
A tree up to 60 ft high; young shoots downy, angled toward the end; buds stalked. Leaves ovate or oval, with a rounded or slightly heart-shaped base, and a short, abrupt point; 3 to 6 in. long, 2 to 4 in. wide; irregularly and often doubly toothed towards the apex, more finely so towards the base; dark green and almost glabrous above, paler and downy beneath, especially along the midrib and veins; primary veins in eight to ten pairs; stalk 3⁄4 to over 1 in. long, downy. Male catkins in clusters of four or five, very slender, up to 6 in. long, expanding sometimes as early as December. Fruits 3⁄4 to 11⁄3 in. long, nodding, solitary or up to as many as five together.
Native of the Caucasus and Persia; introduced, according to Loudon, in 1838, and raised that year from seed in the Birmingham Botanic Garden. It is a handsome, fine-foliaged alder, retaining its leaves until the end of November. There are two at Kew: one, pl. 1900, 62 × 53⁄4 ft, the other, pl. 1923, 55 × 51⁄4 ft (1967). A. cordata is the only other species with which it is likely to be confused, but that differs markedly in its glabrous shoots, its less downy, simply toothed, deeply cordate leaves, and larger fruits.
This species was reintroduced to Kew by Fliegner and Simmons in 1977, from Iran, where it grows by streamsides and in secondary forest in the Elburz mountains, attaining a height in some places of well over 100 ft. Both seed and seedlings were collected, and one of the latter, planted by the Lake in 1978, was 30 ft high by 1982 and produced catkins the following year. The older trees at Kew by the Lake are about 60 ft high and 53⁄4 to 61⁄4 ft in girth. Other examples are: University Botanic Garden, Cambridge, 56 × 8 ft (1982); Talbot Manor, Norfolk, pl. 1951, 66 × 41⁄2 ft (1978); Thorp Perrow, Bedale, Yorks., 60 × 5 ft (1981); Birr Castle, Co. Offaly, Eire, pl. 1929, 58 × 73⁄4 ft (1975).
A. subcordata is likely to be of value as a fast-growing screen on wet sites. It is also in cultivation from seeds collected by Mrs Ala and Roy Lancaster in Iran in 1972.