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The Trees of Great Britain and Ireland

THUJOPSIS DOLABRATA

Thujopsis dolabrata, Siebold et Zuccarini, Fl. Jap. ii. 34, tt. 119, 120 (1842); Franchet et Savatier, Enum. Pl. Jap. i. 469 (1875); Shirasawa, Icon. Essences Forest. Jap., text 27, t. xi, 18–34 (1900).
Thuya dolabrata, Linnæus, Suppl. Pl. System, 420 (1781); Masters, Jour. Linn. Soc. (Bot.), xviii. 486 (1881), and Gard. Chron. xviii. 556, fig. 95 (1882); Kent, in Veitch's Man. Conif. 236 (1900).

The species has been described in detail above.

Two well-marked geographical forms occur, both confined to the main island of Japan:—

1. Var. australis (var. nova). A small tree 40 to 50 feet in height, or a shrub growing as underwood in the dense shade of forests. As a tree it has a slender trunk, with drooping branches and a narrow pyramidal top. Branchlets very flat and only slightly overlapping, the lateral leaves ending in acute points bent inwards. Cones broadly ovoid, with scales thickened at the apex, which is prolonged externally into a blunt triangular process. This is the form which is known in cultivation in Europe, and described and figured in the works cited above.

2. Var. Hondai, Makino.[1] A larger tree, attaining 100 feet in height, with a stem of over 3 feet in diameter. The branch-systems are more densely ramified, the branchlets being placed close together and overlapping one another by their edges more than is the case in the preceding variety. The leaves also are smaller, whiter underneath, and crowded more closely on the shoots; those of the lateral ranks being usually blunt and not curved inwards at the apex. The cones are globular, with scales not thickened at the apex, which is devoid of the process so conspicuous in the other form, or merely shows it as an obsolete transverse minute mucro. The seeds appear to be more broadly winged, the wings being more scarious 1n texture.

This form has not yet been introduced. Elwes has brought home excellent specimens of it in fruit from the Uchimappe Forest, near Aomori, in the extreme north of Hondo. These differ in the characters given above from specimens of the ordinary form obtained by him in the forest of Atera, Kisogawa, and Yumoto (4000 to 5000 feet altitude) in Central Hondo. The smaller leaves, set more closely on densely ramified branchlets in this variety, may be due to the influence of dense shade. The difference in the cone is paralleled by what occurs in the fruit of the different geographical forms of Cryptomera japonica. I am inclined to think that var. Hondai is not a distinct species; but as it is very different, from the point of view of cultivators, it may conveniently bear the name Thujopsis Hondai.

  1. Tokyo Botanical Magazine, 1901, xv. 104.