Page:TheTreesOfGreatBritainAndIreland vol01.djvu/212

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184
The Trees of Great Britain and Ireland

THUYA PLICATA, Giant Thuya

Thuya plicata, D. Don in Lambert, Pinus, ed. 1, ii. 19 (1824); Masters, Gard. Chron. xxi. 214; figs. 69, 70, 71 (1897); Sudworth, Check List Forest Trees U.S. 31 (1898); Sargent, Manual Trees N. America, 75 (1905).
Thuya gigantea, Nuttall, Jour. Philad. Acad. vii. 52 (1834); Sargent, Silva N. America, x. 129, t. 533 (1896); Kent, in Veitch's Man. Coniferæ, 239 (1900).
Thuya Menziesii, Douglas, ex Carrière, Traité Gén. Conif. 107 (1867).
Thuya Lobbi, Hort.
Thuya Craigiana, Hort. [non A. Murray, Bot. Exped. Oregon, 2 (1853)].

A lofty tree, attaining a height of 200 feet, with a trunk remarkably conical, the base being broad and buttressed, sometimes girthing as much as 40 to 50 feet near the ground.

Bark of the trunk Assuring longitudinally in narrow thick plates, which scale off, leaving exposed the reddish brown cortex beneath. On the branches, the bark only begins to scale when they become old and thick. Branches horizontal, ascending towards their ends, forming in England a dense, narrow, pyramidal tree, usually clothed to the base.

The 3-4 pinnate branch-systems, disposed in horizontal planes, have their main axes terete and covered with long leaves ending in acute points which keep parallel to the axes. The glands on these leaves are inconspicuous or absent. On the ultimate axes the leaves are smaller, the flat ones scarcely glandular, and ending in mucronate points; the lateral ones keeled on the back, slightly curved, and ending in sharp cartilaginous points. On the lower surface of most branchlets the foliage is streaked with white, some branchlets usually remaining uniformly green.

The male flowers are dark red in colour, cylindrical, and composed of about 6 decussate pairs of stamens.

The cones when ripe do not remain erect, but are deflected out of the plane of the branchlets. They are oblong, light brown in colour, and composed of 5 to 6 pairs of scales, of which the 2nd, 3rd, and 4th pairs are larger than the others, and fertile. The scales are oval or spathulate, with a rounded apex, from immediately below which externally a small deltoid process is given off. The seeds, 2 or 3 on each fertile scale, are brown in colour, two-thirds the length of the scale, and surrounded laterally by a scarious wing, which is deeply notched at its summit.

Seedling.[1]—The 2 cotyledons are linear, flat, acute at the apex, and slightly tapering towards the base, supported on a terete caulicle, about 35 inch long, which ends in a long brown flexuose primary root giving off a few fibres. The stem, terete and smooth near the base, becomes ridged above by the decunent leaf-bases. The first 4 true leaves are in opposite pairs, decussate with the cotyledons. Above these the stem gives off a number of whorls or pseudo-whorls of longer (½ inch) sharply pointed leaves, dark green above and pale beneath, with markedly decurrent

  1. Figured in Lubbock, Seedlings, ii. 551, fig. 676 (1892), and Sargent, loc. cit. t. 533, fig. 12.