Page:TheTreesOfGreatBritainAndIreland vol01.djvu/57

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AILANTHUS

Ailanthus, Desfontaines, Mém. Acad. Paris, 1786 (1789), 263, t. 8; Bentham et Hooker, Gen. Pl. i. 309 (1862); Prain, Indian Forester, xxviii. 131, Plates i. ii. iii. (1902).

Lofty trees with very large alternate imparipinnate leaves. Flowers small, polygamous, bracteolate, in panicles. Calyx 5-toothed, imbricate. Petals 5, valvate, disk 10-lobed. Stamens 10 in the staminate flowers, 2–3 in the hermaphrodite flowers, and absent in the pistillate flowers. Ovary present in pistillate and hermaphrodite flowers, rudimentary in staminate flowers, deeply 2–5 cleft with connate styles: ovules 1 in each cell. Fruit of 1–5 samaras, with large membranous wings, each samara containing 1 seed.

Ailanthus belongs to the Natural order Simarubeæ, and consists of about eleven species occurring in India, Indo-China, China, Java, Moluccas, and Queensland. Most of the species are tropical trees, Ailanthus glandulosa being until lately the only species which was known to occur in temperate regions; but Ailanthus Vilmoriana, Dode,[1] must be here mentioned. This is a tree remarkable for its prickly branchlets, of which only one specimen is known, namely, a young, healthy, vigorous tree grown in M. de Vilmorin's garden at Les Barres.[2] It was raised from seed sent by Père Farges in 1897 from the mountains of Szechuan in Central China;[3] and is certainly a very distinct species. I saw it in the summer of 1904, and in general aspect there is little to distinguish it from the common species. It is now about 20 feet in height. The leaflets in this species are less abruptly acuminate, not falcate, much duller above and paler beneath, with larger glands than in Ailanthus glandulosa. All the parts of the tree are much more pubescent than in that species.

Ailanthus grandis,[4] Prain, a new species from Sikkim and Assam, which attains 120 feet high, may be here mentioned, as it is possible that it might be grown in Cornwall or in Kerry. It has not yet been introduced.

  1. Revue Horticole, 1904, p. 445, fig. 184.
  2. Figured in Fruticetum Vilmorinianum, 1904, p. 31; where it is called Ailanthus glandulosa, var. spinosa.
  3. Mr. E.H. Wilson informs us that it is very common in the valleys of the Min, Tung, and Fou rivers, between 2000 and 4500 feet. He says that it is much more spiny in the young than in the adult state, and that it has much larger foliage than the common species. A plant is now growing at Kew, and is referred to by Mr. Bean in Gardeners' Chronicle, xxxviii. 276(1905).
  4. Indian Forester, xxviii. 131, Plate i. (1902).

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