The Trees of Great Britain & Ireland/Volume 2/Cladastris

by Henry John Elwes and Augustine Henry

 

CLADRASTIS

 

Cladrastis, Rafinesque, Cincinnati Literary Gazette, i. 66 (1824); and Neogeniton, i. (1825); Bentham et Hooker, Gen. Pl. i. 554 (1865).

Maackia, Ruprecht et Maximowicz, Mél. Biol. ii. 440, t. ii. (1856).

 

Deciduous trees or shrubs belonging to the division Papilionaceæ of the order Leguminosæ. Leaves alternate, unequally pinnate; leaflets opposite, sub-opposite or alternate, on stout petiolules, entire in margin, and without stipels. Flowers in panicles or racemes, on slender pedicels; calyx with four or five short unequal teeth; corolla papilionaceous, petals unguiculate, standard nearly orbicular, wing and keelpetals oblong; stamens ten, free or slightly united at the base; anthers versatile; ovary with numerous ovules; style incurved, subulate; stigma terminal, minute. Pod linear, flattened, thin, thickened on the upper margin; valves membranous; seeds four to six.

Four species of Cladrastis have been described, constituting two sections, which have been considered by Sargent and other botanists to form two distinct genera, Cladrastis and Maackia. The difference in the buds of the two sections is remarkable; but analogous differences occur in other genera, as Carya and Pterocarya; and in the absence of important differential characters in the flowers and fruit, it is advisable to unite the sections into one genus.

 

Section I. Eu-Cladrastis.

Buds several together, compressed into a cone, and concealed in the base of the petiole of the leaf. Leaflets usually alternate. Flowers in panicles; calyx five-toothed.

1. Cladrastis tinctoria, Rafinesque. Kentucky, Tennessee, Alabama, and N. Carolina.

Shoots glabrous. Leaflets seven to eleven, oval or ovate, acuminate, almost completely glabrous.

2. Cladrastis sinensis, Hemsley. Central and western China.

Shoots rusty pubescent towards the base. Leaflets nine to eleven, oblong-lanceolate, obtuse or sub-acute, rusty pubescent towards the base and along the midrib.

 

Section II. Maackia.

Buds solitary, axillary, not concealed. Leaflets opposite or sub-opposite. Flowers in racemes; calyx four- or five-toothed.

3. Cladrastis amurensis, Bentham et Hooker. Amurland, E. Manchuria, Korea, and Japan.

Shoots pubescent. Leaflets nine to eleven; deltoid, ovate or oval; obtuse or acute; densely appressed pubescent; calyx four-toothed.

4. Cladrastis Tashiroi, Yatabe.^[1] Loochoo Islands.^[2]

Allied^[3] to C. amurensis, but always a small shrub; with smaller leaflets, acute and not truncate or rounded at the base as in that species, glaucescent and scarcely pubescent beneath. Flowers and pods also smaller; calyx five-toothed.

 

CLADRASTIS TINCTORIA, Yellow-Wood

 

Cladrastis tinctoria,^[4] Rafinesque, Neogeniton, i. (1825); J.D. Hooker, Bot. Mag. t. 7767 (1901).

Cladrastis fragrans, Rafinesque (name only), Cincinnati Literary Gazette, i. 66 (1824).

Cladrastis lutea, Koch, Dendrologie, i. 6 (1869); Sargent, Silva N. America, iii. 57, tt. 119, 120 (1892), and Trees N. America, 568 (1905).

Virgilia lutea, Michaux, Hist. Arb. L'Amér. iii. 266, t. 3 (1813); Loudon, Arb. et Frut. Brit. i. 565 (1838).

 

A tree attaining 60 feet in height, and rarely 12 feet in girth. Bark smooth and silvery grey. Branchlets brittle, glabrous. Leaves (Plate 125, fig. 5) alternate, unequally pinnate, 8 to 12 inches in length. Leaflets seven to nine, usually alternate; the terminal one largest, articulate and directed to one side, often broadly rhombic; the others gradually diminishing in size towards the base of the leaf, 3 to 4 inches long by 14 to 2 inches wide, on stout pubescent petiolules, oval or ovate, entire and non-ciliate in margin; base broadly cuneate or rounded, apex acuminate; upper surface light green and glabrous; lower surface pale green with occasional hairs on the midrib and veins. Rachis of the leaf terete, glabrous, with the base swollen and hollowed out, enclosing the buds, which are usually four, the largest and uppermost one developing, the others minute and rudimentary.

Flowers in nodding terminal panicles, 10 to 20 inches long, white, with a yellow spot at the base of the standard. Pedicels slender and not grouped in pairs. Calyx canpanulate, enlarged on its upper side; teeth five, short, obtuse, nearly equal. Corolla papilionaceous with clawed petals; standard nearly orbicular; wings oblong and two-auricled at the base; keel-petals free, oblong, and sub-cordate or two-auricled at the base. Stamens ten, free, Ovary linear, stalked, villose; ovules numerous. Pod glabrous, short-stalked, linear, glabrous. Seeds four to six, attached by slender stalklets, oblong-compressed, without albumen.

 

Seedling

A plant, raised from seed sown at Colesborne on 2nd March, showed the following characters on 7th July:—Root white, fleshy, tapering, 3 inches long, giving off numerous lateral fibres. Caulicle striated, glabrous, 1½ inch long. Cotyledons two, sub-sessile, oblong, tapering slightly at the base, broader towards the rounded apex, green above, white beneath, coriaceous, entire. Stem terete, with a few scattered hairs below, densely white pubescent above. Leaves, all with petioles swollen at the base; first pair opposite, on pubescent stalks, simple, ovate, entire, 2 inches long by 14 inch broad. The third, fourth, and fifth leaves are alternate; the third simple and like the first pair; the fourth and fifth trifoliolate on a stalk 2 inches long, terminal leaflet ovate, lateral leaflets oval and smaller.

 

Identification

Cladrastis tinctoria is readily distinguishable in summer by the pinnate leaves with alternate leaflets, of which the terminal one is directed to one side of the leaf; and by the swollen base of the petiole, which encloses and conceals the buds.

In winter the following characters are available (Plate 126, fig. 4):—Twigs zigzag, shining, brown or grey, terete, glabrous; lenticels minute, numerous. Leaf-scars alternate, obliquely set on slightly prominent pulvini, oval, whitish, with five bundledots on the outer rim, the centre of the scar being occupied by a projecting cone, which consists of four buds compressed together and superposed one above the other, the uppermost one the largest, all pubescent. Terminal bud not formed, the apex of the twig showing a small circular scar or a short stump, indicating where the top of the branchlet fell off in early summer.

 

Distribution

Cladrastis tinctoria is one of the rarest trees in the American forest, growing only in a few isolated localities in central Kentucky, central and eastern Tennessee, northern Alabama, and the south-western part of N. Carolina. It is met with on limestone ridges and cliffs, usually in rich soil, and frequently overhangs mountain streams. (A.H.)

 

Cultivation

The yellow-wood is a favourite ornamental tree in American gardens, where, according to Sargent,^[5] it adapts itself readily to varied conditions of soil and climate, though it requires deep rich soil in order to attain its full size and beauty. It has a tendency, however, which in England is equally marked, to divide into several spreading stems, which are rather brittle and liable to split the trunk. Its long racemes of white fragrant flowers make it a very pretty tree early in June, but in our climate these are not produced as freely as in America, and I have never seen fruit ripened in this country. In autumn the leaves turn a bright yellow.

Sargent^[6] gives an illustration of a beautiful specimen in a garden near Boston which, 35 years after planting, was 35 feet high and had a spread of nearly 60 feet. I saw several in this district, but none so large as those which I have seen in England.

Though it germinates quickly, and seems easy to raise from seed, the tree is now seldom planted in England, but may be recommended for warm sheltered situations in good soil in the south and east, though perhaps the damp climate of the west does not suit it; and as most of the trees mentioned by Loudon have disappeared, it seems to be short-lived in this country. The seedlings which I have raised from American seed are fairly hardy, and after the first two years grow better than many American trees on my soil.

This species was introduced into cultivation in England in 1812, by John Lyon, a Scotsman who travelled in Carolina, Georgia, and Florida.

 

Remarkable Trees

The largest tree known to us is at Syon (Plate 124), which in 1904 was no less than 60 feet in height by 7 feet in girth and still a fine tree, though its trunk is decaying inside. There is another in Kew Gardens, near the Director's office, which measures 35 feet high, with a bole of 3 feet girthing 5 feet 4 inches and dividing into six main stems, which sub-divide into numerous upright branches. At the Knaphill Nursery near Woking is a very well grown tree about 45 feet high and 8 feet in girth, the head spreading to 16 yards in diameter.

At Highclere there is a tree which measures 42 feet by 7 feet with a spread of branches of 45 feet. Although there is some decay near the root the tree seems to have become more vigorous recently. At Blenheim there is an old specimen, with a stem divided close to the ground, and forming rather a large bush than a tree. At Cornbury Park there is also a fair-sized tree. At Barton, Suffolk, a tree planted^[7] in 1832 was in 1904 25 feet high with a short bole, 5 feet 6 inches in girth, dividing into three wide-spreading main branches.

We have not seen any large enough to mention in Scotland or Ireland.

 

Timber

The wood, according to Sargent, is heavy, hard, strong, and close-grained, and is susceptible of a fine polish. At one time it was used in Kentucky for making gun-stocks; but is too rare to have any commercial importance. It produces a yellow dye. (H.J.E.)

 

 

Plate 124: Yellow-Wood at Syon

Plate 124.

YELLOW-WOOD AT SYON

 

 

CLADRASTIS AMURENSIS

 

Cladrastis amurensis, Bentham et Hooker, Gen. Pl. i. 554 (1865); Maximowicz, Mél. Biol. ix. 72 (1873); Franchet et Savatier, Enum. Pl. Jap. i. 115 (1875) and ii. 327 (1879); J.D. Hooker, Bot. Mag. t. 6551 (1881); Shirasawa, Icon. Ess. Forest. Jap. text 85, pl. L. figs. 1–12 (1900).

Maackia amurensis, Ruprecht et Maximowicz, Mél. Biol. ii. 418, 441 (1856) and 534 (1857); Maximowicz, Prim. Fl. Amur. 87, 390, t. v. (1859); Morren, Belgigue Horticole, 1890, p. 301, t. 18; Gartenflora, 1875, p. 152.

 

A small tree, attaining 40 or 50 feet in height, with bark peeling off in old trees like that of a birch. Young shoots minutely pubescent. Leaflets (Plate 125, fig. 6) seven to eleven, opposite or rarely sub-opposite, the terminal one articulate, the lateral ones on short, stout pubescent petiolules; 2 to 3 inches long; deltoid, ovate or oval; base truncate or rounded; apex obtuse or acute; entire; upper surface dark green and minutely pubescent; lower surface pale green, densely appressed pubescent; rachis pubescent, swollen at the base.

Flowers greenish white, on long pedicels, in simple or occasionally branched erect terminal dense racemes. Calyx teeth four, short, broad, unequal. Petalclaws long, slender; standard obovate, emarginate; wings oblong, obtuse, twoauricled at the base; keel petals partially coalesced, one-auricled. Stamens slightly connate below. Pod, 2 to 3 inches long, oblong, flattened, brown, slightly appressed pubescent; seeds, one to five, oblong.

In specimens from the Asiatic continent the leaflets are larger and much less pubescent than in the Japanese tree, which has been distinguished by Maximowicz as var. Buergeri,^[8] and is characterised by very dense appressed pubescence on the lower surface of the leaflets and white tomentose shoots.

In winter the twigs (Plate 126, fig. 5) are shining, glabrous; leaf-scars on prominent pulvini, semicircular, marked by a central large tubercular bundle-scar and two minute dots close to the upper margin; true terminal bud absent, the top of the branchlet having fallen off in early summer and leaving a short stump at the apex of the twig. Buds solitary, dark brown, shining, pubescent towards the apex, showing two scales visible externally.

Cladrastis amurensis occurs in Amurland as far north as lat. 52° 20', and grows throughout Eastern Manchuria and Korea, the largest tree seen by Maack being only 35 feet high and 1 foot in diameter. According to Shirasawa, it is met with in Japan on moist rich soils in the temperate parts, ascending to 4300 feet in the central chain of the main island, and attaining a height of 50 feet and a diameter of 28 inches. It was collected by Elwes in the forest near Asahigawa in central Hokkaido, where, however, it was not abundant or conspicuous. It is called Inu-enju in Japan.

Cladrastis amurensis was introduced from the Amur in 1864 by Maximowicz; and has been spread throughout Europe by the St. Petersburg Botanical Garden. It probably came into England about 1870.

It is propagated either by seed or by root-cuttings. At Kew it is rather a shrub than a tree, and produces flowers when quite young, which appear late in the season, in the end of July or the beginning of August. It ripens its fruit in October, the pods remaining on the tree during winter.

The timber, according to Shirasawa, is hard and tenacious, and is used in building and in making furniture. Elwes purchased planks of it at Sapporo, which are of a yellowish-brown colour, and seem to be of good quality for cabinet-making. (A.H.)

 

CLADRASTIS SINENSIS

 

Cladrastis sinensis, Hemsley, Journ. Linn. Soc. (Bot.) xxix. 304 (1892).

 

A tree attaining 70 feet in height and 10 feet in girth. Young shoots rusty pubescent towards the base. Leaflets nine to eleven, alternate, entire, oblonglanceolate, obtuse or acute at the apex; broad and rounded, rarely cuneate, at the base; lower surface with appressed pubescence most marked towards the base and along the midrib. Leaf-rachis pubescent, with swollen base enclosing two or three buds. Leaf-scars on older shoots, oblique on prominent pulvini, orbicular; the raised circular rim, discontinuous above, surrounding a central densely pubescent depression, in which lie two or three buds, the upper one of which is the largest.

Flowers pinkish-white, fragrant, in large terminal, rusty-pubescent panicles. Calyx rusty-pubescent; teeth short, broad, rounded. Petals long-clawed, erect, free; standard broadly obovate, bifid; wings and keel-petals oblong. Stamens slightly connate at the base; ovary pubescent. Pod linear-oblong, flattened, with thickened margins.

This tree, which resembles Sophora japonica in habit and foliage, was discovered by Pratt, in 1890, in Western Szechuan, where E. H. Wilson subsequently saw large trees at 7000 feet altitude in the Hsiang Ling range, west of Mt. Omei. It also occurs in the high mountains of the Fang district in Hupeh, from whence seeds were sent home by Wilson in 1901. Plants raised at Coombe Wood were, in 1906, 5 feet high, and for so far have proved perfectly hardy. The tree has beautiful flowers, and, growing at high altitudes in western China, should thrive in this country. (A.H.)

 

Printed by R. & R. Clark, Limited, Edinburgh.

 

 

Plate 125: Pterocarya, Gymnocladus, Cladrastis, and Cedrela; leaves

Plate 125.

PTEROCARYA,GYMNOCLADUS, CLADRASTIS AND CEDRELA

 

 

Plate 126: Liriodendron, Cedrela, Ailanthus Cladrastis, and Corylus; twigs and buds

Plate 126.

LIRIODENDRON, CEDRELA, AILANTHUS, CLADRASTIS AND CORYLUS

 

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1. Tokyo Bot. Mag. vi. 345, t. 10 (1892).
2. Cf. Ito and Matsumura, Journ. Science College, Imp. Univ. Tokyo, xii. 436 (1899).
3. Judging from the description, as I have seen no specimens. There are specimens in the Kew Herbarium (Cladrastis, sp.? Hemsley, Journ. Linn. Soc. (Bot.) xxiii. 201 (1887)) which were collected by Millett, probably in the vicinity of Canton, which are very near to the Loochoo species.
4. This name is adopted as being the first one with a description published under the correct genus.
5. Garden and Forest, i. p. 92.
6. Garden and Forest, i. p. 92.
7. Bunbury, Arboretum Notes, p. 1.
8. Mél. Biol. ix. 72 (1873).