The Trees of Great Britain & Ireland/Volume 1/Sophora

by Henry John Elwes and Augustine Henry

 

SOPHORA

 

Sophora, Linnæus, Gen. Pl. 125 (1737); Bentham et Hooker, Gen. Pl. i. 555 (1865).

 

Trees, shrubs, or perennial herbs, with naked buds and imparipinnate leaves. Flowers papilionaceous, in simple racemes or terminal leafy panicles. Calyx five-toothed, imbricate. Stamens ten, not united together, or rarely sub-connate. Ovary short-stalked, with many ovules. Pod moniliform, indehiscent, or tardily dehiscent.

The name Sophora was taken by Linnaeus from the Arabic word Sophera, which indicated some leguminous tree. The genus belongs to the tribe Sophoreæ (Natural order Leguminosæ, division Papilionaceæ) characterised by imparipinnate leaves and ten free stamens. There are about twenty-five species of Sophora, generally spread throughout the tropical and warm temperate regions of the globe. The only species of importance which attain to timber size are Sophora japonica and Sophora platycarpa. Sophora macrocarpa from Chile and Sophora tetraptera from New Zealand are shrubs or small trees, which are frequently cultivated in the southern counties of England, and do not come within the scope of our work, although they are said to attain a height of 50 feet in the wild state.

Sophora platycarpa, Maximowicz, in Mel. Biol. ix. 70 (1873), (Fuji-ki in Japan), only lately^[1] introduced into cultivation in England; but in the United States, where it has been grown for some time, it is said to have proved hardier than Sophora japonica.^[2] It is a tree of considerable size, occurring in woods in Japan on the side of Fusiyama and in Nambu. It is similar in leaves and flowers to Sophora japonica; and, as will be pointed out in our account of that species, has been probably confused with it by writers on Japanese trees. The leaves are larger than in Sophora Japonica, the leaflets being 2 to 3½ inches long, alternate, acuminate, glabrous or nearly so. The flowers are ½ inch long, white, and loosely arranged. The main difference is in the pod, which is membranous, flat, narrowly winged on each side, and irregularly constricted.^[3]

 

SOPHORA JAPONICA, Sophora Tree

 

Sophora japonica, Linnæus, Mantissa i. 68 (1767); Loudon, Arb. et Frut. Brit. ii. 563 (1838); Shirasawa, Iconographie des Essences Forestières du Japon, i., Text, p. 86, Plate 50 (1900).

 

A large tree, with a straight cylindrical stem of considerable height in some cases, but more often in cultivated examples dividing at no great distance above the base; branches tortuous, with pendent tips; crown of foliage, large, broad, and rounded in shape. Bark brown or greyish and scaly, fissured longitudinally, but to no great depth; on young shoots and older branchlets, smooth and dark green.

Leaves deciduous, alternate, unequally pinnate, with nine to fifteen leaflets, which are sub-opposite, oval, pointed at the apex, often ending in a short bristle, dark green and opaque above, glaucous beneath. In the ordinary cultivated form they are apparently glabrous, but with a lens minute hairs may be detected on both surfaces. The petiolules are velvety; the main stalk is greenish, swollen at the base, and slightly pubescent. In certain wild specimens from China they are green and not glaucous beneath; and in Hupeh a well-marked variety occurs, in which the under surface of the leaflets, the petiole, and young shoots are densely white pubescent.

Flowers in large, loosely branched terminal panicles. They are somewhat variable in colour; in Central China white, at Canton a bright yellow, in cultivation in England pale yellow, sometimes tinged with purple. Calyx small, bell-shaped, five-toothed. Corolla, standard large, obtuse, round, recurved; wings oval-oblong; keel semi-orbicular, rounded, and of the same length as the wings. Pod long-stalked, 1 to 2 inches long, glabrous, fleshy, compressed, with a beak at the apex, and constricted between the seeds, which are one to five in each pod, dark brown in colour and kidney shaped.^[4]

In England the tree produces flowers regularly, late in the season, in August, September, and October, but seldom if ever fruits.

 

Identification

Sophora japonica is readily distinguished in summer by the leaves, the characters of which have been already given, and by the branchlets, which are angled, very smooth and dark green, both in the young shoots and those of the second year. When the young shoots are cut they emit a strong peculiar odour. In winter the characters of the buds and branchlets must be noted. The buds are spirally arranged on the shoots; solitary or in pairs, one placed above the other; naked, i.e. not surrounded by any true scales, and dark violet densely pubescent. They are very small and lodged in the leaf-scar, which is oval, with the bud in the centre, and displays three crescentic small cicatrices left by the vascular bundles of the petiole. The leaf-scar is set obliquely on a projecting leaf-cushion. The branchlets in winter are the same as in summer, but they show more clearly their zig-zag nature, and at their apex will generally be seen a little stub which indicates the point where the end of the branchlet fell off in summer, no true terminal bud being developed. Occasionally a true terminal bud may be seen at the apex of the shoot, which is open and not concealed in the leaf-scar, minute, bearing two scales outwardly, and very pubescent.^[5]

Varieties

In addition to the pubescent form of Central China, not yet introduced, a few varieties occur, concerning the origin of which little is known.

Var. variegata.—Leaves dull yellowish white in patches. This form is neither robust in growth nor attractive in appearance.

Var. pendula^[6] (Weeping Sophora).—One of the most formal of weeping trees. It is usually grafted by budding on seedlings of the common Sophora about 6 to 8 feet high; and from this elevation the branches hang down until on reaching the ground their tips spread out or turn up. It can be used as an arbour; and even in winter the light, smooth, green branches make it ornamental. The only trouble is in procuring smooth, straight stems of the ordinary Sophora of a sufficient height. F. L. Temple^[7] says: "In spring plant dormant Sophoras about ¾ inch in diameter in the fairly rich earth bottom of a greenhouse. Cut them back to the ground, and set them 1 foot apart each way; and by December first they will be out of the top of the house and as smooth as willows. Then lift and keep them protected in a cellar or frame, or heel them deep in a well-drained place till spring, when they can be planted in nursery rows, and grafted at the same time with the most gratifying results." With regard to the origin of the weeping Sophora nothing is known definitely; but Fortune^[8] states that at Shanghai in 1853 he saw "pretty specimens of Sophora japonica pendula, grafted high as we see the weeping ash in England."

It is probable that this variety was imported early from China.

Var. crispa.—Leaves curled, the points of the shoots resembling as it were clusters of ringlets. We have never seen a specimen of this curious variety, which is not mentioned in the Kew Hand-list.

Var. Korolkowii (Sophora Korolkowii, Cornu).^[9]—This has longer and narrower leaflets than the type, and the young shoots, leaf-stalk petiole, and under surface of the leaflets, are whitish pubescent. The flowers are said to be of a dirty white in colour. Kohne^[10] states that one of Dieck's introductions from Mongolia is identical with the plant cultivated at Segrez under this name, the origin of which is unknown. In the summer of 1904 I visited the Arboretum at Segrez, and saw this specimen, which is about 30 feet high with a stem a foot in diameter, bearing a large roundish crown like the common Sophora. In the absence of flowers or fruit, it is impossible to say whether it is a distinct species; but in foliage and other characters it differs so little from Sophora japonica, that probably Zabel^[11] is correct in considering it to be only a form of that species. It seems to be well worth cultivation, judging from the vigorous growth and dense foliage of the fine specimen at Segrez.

Var. violacea.—This variety has also whitish pubescence on the shoots, petiole, and under surfaces of the leaflets, which are longish, with an acute or acuminate apex. The flowers are violet according to Dieck.^[12] It does not appear to be in cultivation in England.

I incline to the belief that we have in these forms to deal with only two varieties of Sophora japonica, which is a widely spread species, and presents considerable variation in pubescence and in colour of the flowers in China.

Var. oligophylla, Franchet.^[13]—This is a curious variety found by Père David at a tomb near Peking, where he observed two trees. The leaflets are very few in number, three or four, and the end one is trilobed; they are thicker in texture and more glaucous than is ordinarily the case. This variety would be well worth introduction.

 

Distribution and History

Sophora japonica, in spite of its name, does not appear to be really wild in Japan, although it is recorded from that country by Franchet^[14] and Matsumura.^[15] Shirasawa,^[16] the latest Japanese authority, says it is planted around habitations in both the sub-tropical and temperate regions of Japan, and that it was introduced from China. Sargent^[17] observes: "Even Rein (The Industries of Japan), usually a most careful observer, states that 'Sophora japonica is scattered throughout the entire country, especially in the foliaceous forests of the north.' He had evidently confounded Sophora with Maackia,^[18] a common and widely spread tree, especially in Yezo. Sophora, which is only seen occasionally in gardens, does not appear to be a particularly popular tree with the Japanese." The Kew Herbarium specimens from Japan are from gardens near Nagasaki, no wild specimens having been ever received.

Sophora japonica is undoubtedly a native of China, and it is recorded from nearly all the provinces where Europeans have made botanical collections; but of its occurrence as a forest tree there is little information. It appears to be really wild in the province of Chihli. I have never seen it in the numerous mountain forests which I visited in Central China or Yunnan; and it is difficult to decide whether the trees seen at lower levels, where cultivation has been going on for centuries, are wild or planted. It has a wide range as a cultivated plant in China, as it flourishes from Pekin to Hongkong and from Shanghai to Yunnan.

It has been known to the Chinese from the earliest times, and has been always named by them the Huai tree. In the Chou Li, a Chinese classical book, dating from several centuries before the Christian era, it is mentioned as having a place in official audiences. In front of the high officials were placed three Sophora trees, beside which stood the counsellors. It was also used as firewood, and was planted in cemeteries, being the tree prescribed by law to be planted beside the tumulus, 4 feet high, in which officials of low degree were buried. The tumulus of the emperor was 30 feet high, and around it pine trees were planted. Feudal princes were honoured with cypresses; and common people were only permitted to have willows around their tombs. The Sophora was also used medicinally from the earliest times in China, the flowers, fruit, bark, and root being all employed. In the Erh-ya, the oldest Chinese dictionary (twelfth century b.c.), the Huai tree is called the guardian of the palace; and it is said to open its leaves by night and close them by day. The text is probably corrupt, and the periods of expanding and folding of the leaves are reversed. This is perhaps the first reference in any literature to the phenomenon of the sleep of plants. The term guardian of the palace no doubt refers to its use in official audiences.

With regard to the uses of Sophora in China at the present day, in addition to its ornamental character as a tree planted frequently in the courtyards of temples, it is also of considerable economic importance. In commerce the flower-buds (Huai-mi, huai-hua, huai-tze), and pods (huai-chio, huai-shih) are met with everywhere; but considerable confusion has arisen in books as to the exact uses of these products. Shirasawa (l.c.) is inaccurate in stating that the Chinese use the bark to dye paper and cloth of a yellow colour. Mouillefert^[19] says the leaves are used for dyeing; but this is also an error. The facts are simple: the flower-buds are used as a dye, and the pods as a medicine.

The flower-buds, as seen for sale, are mixed with stalks, etc., and are evidently collected when quite young as they are only about ⅛ to ¼ inch long. They are oval and pointed at the stalked end, dark greyish in colour, and tasteless. When immersed in water they impart to it a fine yellow colour. These flower-buds, packed in large sacks, are exported in considerable quantity from Shanghai and Tientsin. Consul Meadows in a letter to Kew gives an account of the process of dyeing, which is one for dyeing blue cloth a green colour rather than for obtaining a yellow colour.^[20] Debeaux^[21] asserts that the buds are moistened with water, and a quantity of common salt is added; the mixture is then put in a press, which squeezes out a liquor with which cotton or silk may be dyed yellow. He adds that the leaves do not contain any yellow colouring matter.

Every part of the tree abounds in a purgative principle; and it has been asserted that it is dangerous to work with the wood when it is fresh, owing to the distressing symptoms which ensue; and turners of the wood suffer especially. The active principle resembles the cathartine which occurs in senna leaves. In the botanical garden at Dijon there is a well beneath a Sophora tree, and when its leaves or flowers are about to fall the gardener covers the well, having found by experience that the water acquires laxative properties by the infusion in it of the Sophora leaves or flowers.^[22]

The wood, according to Shirasawa (l.c.), differs remarkably in the colour of the heart-wood and sap-wood; the specific gravity is in dry air 0.74. It is tough and durable, though light and coarse grained; and the annular layers are marked by broad bands of open cells. In Japan it is used for the pillars and frames of their wooden houses, but is not of sufficient importance to have been included in the Japanese Forestry exhibit at St. Louis, nor is it mentioned in Goto's Handbook of the Forestry of Japan as a valuable wood.

 

Introduction

Petiver^[23] (1703 or a little earlier) speaks of "Hai-hoa, Chinensibus, flore albo, siliquis gummosis articulatis," evidently the Sophora, and it is probable that the specimen was collected in the island of Chusan by Cunningham in 1700.

Desfontaines,^[24] quoting Guerrapain,^[25] states that the tree was first raised in Europe from seeds sent by Père d'Incarville (a Jesuit stationed at Peking) in 1747, the first trees being planted at the Petit Trianon by B. de Jussieu. It was unknown to what genus the tree belonged, until it flowered near Paris in 1779. It was introduced in 1753 into England by James Gordon, a celebrated nurseryman at Mile End.^[26] Mr. Nicholson obtained from Mr. James Smith, former curator of Kew Gardens, some interesting details concerning the Kew trees. Five plants were early planted at Kew, all of which were still there in 1864, but two no longer exist. One of the three trees remaining is near the rockery; not far off is the famous specimen in chains, while the third tree is in the village at Kew beside the house once occupied by Mr. Alton, the first director of the Kew Gardens. These three trees, according to Mr. Nicholson,^[27] are probably as old as any existing elsewhere in England. There is, however, another tree at Kew beyond the Pagoda of which there is no history.

 

Cultivation

Sophora japonica is an ornamental tree, the peculiarities of which make it interesting. The leaves are dark, glossy green, of an unusual tint, and the younger branchlets are of the same colour. The leaves fall very late in autumn, and keep on the tree fresh and green long after most trees have lost their foliage. The time of flowering is also very late, and this is a point of interest, although the flowers are not conspicuous or remarkable for size or colour. It is a very hardy tree in England,^[28] and seems to be free from all attacks of fungi and insects. Its roots do not sucker, which is a point in its favour when planted in towns or in gardens or parks. It has been freely used as a street tree in Italy, where its dense foliage is an advantage in the hot summers. It is remarkable how little the foliage is affected by the hottest and driest seasons, and on this account it might be tried in dry and hot situations. It thrives fairly well in all soils that are deep and not too compact, but it will only grow vigorously in deep rich soils, where seedlings will sometimes attain a height of 12 feet in four or five years.^[29] It is propagated by seeds, which should be sown in spring.

 

Remarkable Trees

The trees in the Kew Gardens have been alluded to as regards their history. The one which occurs near the Pagoda, in 1903, was 68 feet high and 8 feet 3 inches in circumference. The old tree, with the branches held together by chains, now measures (1905) 50 feet high and 13 feet in girth at a foot from the ground, the narrowest part of the short bole, which branches immediately into three main limbs. A fourth limb, very large, was blown off some years ago. Not far off is a smaller tree about 6 feet in girth near the ground; it branches from the base, forming a wide-spreading low tree.

At Syon, two trees of considerable size are now living, each about 70 feet high; one measured in 1903 12½ feet in girth, the other 12 feet.^[30]

The tree in the Oxford Botanic Garden was 65 feet high by 12 feet 3 inches in girth in 1903 when measured by Elwes.^[31]

That in the old Botanic Garden at Cambridge is one of the finest trees in England, as it has a very symmetrical bole. It measured in 1904, 73 feet high by 11 feet in girth. It is figured in Plate 16.^[32]

We are not acquainted with any large specimens of the Sophora now growing in Scotland, Ireland, or Wales, though Loudon mentions one at Tyninghame, Haddingtonshire, 42 feet high,^[33] one at Castletown near Dublin 35 feet high, and one at Oriel Temple, Co. Louth, of the same height.

In France and Germany there are probably larger specimens than in this country. (A.H.)

 

1. There are two plants at Kew which were raised from seeds obtained in 1896 from Späth of Berlin. See Mittheil. der Deut. Dendr. Gesell. 1896, p. 27.
2. A. Rehder in Bailey's Cyclopedia of American Horticulture, p. 1684 (1902).
3. Sophora shikokiana, Makino, in Tokyo Botanical Magazine, 1900, p. 56 (Yuko-noki in Japan), is described as a species closely allied to S. platycarpa, and as being widely distributed throughout the mountain districts of Japan. It is said to be a tree of considerable size.
4. Seedling.—Seeds sown early in the year at Colesborne produced two or three young plants, which showed the following characters in July:—Caulicle an inch or more in length, terete, green, glabrous, ending in a long whitish tap-root with numerous lateral fibres. Cotyledons oblong-spathulate, ⅝ inch long, entire, rounded at the apex, tapering at the base, sub-sessile, coriaceous, dark green and minutely pubescent above, pale green below. Stem white appressed pubescent, giving off alternately about six compound leaves; the lower three with five leaflets, the terminal leaflet being larger and broader in proportion to its length than the others; the upper three with 7 to 9 leaflets, uniform in size and shape; all the leaflets oval, entire, shortly-stalked, their under surface with a scattered appressed pubescence, dense on the midrib. Small ovoid densely pubescent buds are produced, one in the axil of each leaf, the shoot being terminated by an oblong white pubescent larger bud.
5. A Plate showing buds will appear in a later part.
6. An excellent article upon different species of weeping trees was published in the Gardeners' Chronicle, 1900, xxviii 477; and on p. 479 there is a good figure of a fine specimen of the weeping Sophora.
7. Garden and Forest, 1889, 164.
8. Fortune, Residence among the Chinese, 139.
9. Cornu's name is given on the authority of Zabel, in Laubholz-benennung (1903), p. 256. We have been unable to find Comu's description of the species.
10. Köhne, Dendrologie, 1893, p. 323.
11. See note 5 supra.
12. Köhne, loc. cit.
13. Franchet, Plantæ Davidianæ, i. 100 (1884).
14. Franchet et Savatier, Enum. Plant. in Japonia, i. 115.
15. Matsumura, Shokubutsu-mei-i, 279 (1895).
16. Shirasawa, loc. cit., Text, i. 86. The tree is called Enju in Japan.
17. Sargent, Forest Flora of Japan, I.
18. Maackia is another name for Cladrastis amurensis; but it is possible that the tree confused with Sophora japonica in Japan is Sophora platycarpa, Maxim, which is very similar to it in foliage. Dupont, Les Essences Forestières du Japon, p. 66, gives a very complete account of the wood and the uses of a forest tree in Japan, which he considered to be Sophora japonica; but as it is evidently not that species, and as it is uncertain whether he referred to Sophora platycarpa or Cladrastis amurensis, I have not quoted his description.
19. Mouillefert, Traité des Arbres, 629.
20. The process, according to Meadows, is as follows:—"To dye a piece of cotton cloth of narrow width (1½ feet) a thousand feet long, a mixture is made of 42 lbs. of Sophora buds, 8 lbs. of alum, and 666 lbs. of water, which is boiled in a large pot for six hours. In Chekiang both cottons and silks are first dyed a light blue, and are then put in the mixture just described, and all is boiled over again for three or four hours; the cloth is then taken out and dried in the sun. It is afterwards boiled and sun-dried once or twice again, according as a lighter or darker tint of green is required."
21. Debeaux, Note sur quelques matières tinctoriales des chinois (1866).
22. Loudon (ii. 564), quoting from Duhamel, states that the bark and green wood of this tree exhales a strong odour which produces on those who prune it a remarkable effect. A plank cut from a tree at Kew in Elwes' possession shows a hard, compact, yellowish brown wood.
23. Petiver, Musei Petiveriani Centuriæ decem rariora Naturæ continens, No. 930 (1692–1703).
24. Desfontaines, Histoire des Arbres, ii. 258 (1809).
25. Guerrapain, Notice sur la culture du Sophora.
26. Hort. Kew, first edition (1789), ii. 45. In Andrews Repository, ix. 585, there is a figure of a specimen from a tree 40 feet high in the collection of John Ord at Purser's Cross, Fulham, which was planted by him forty years before. Ord is stated to have received his plants from Gordon, "who introduced the species from China in 1753." It is also stated that the Sophora first flowered in England at Syon in August 1797. Loudon, however (loc. cit.), states that "the oldest tree near London is at Purser's Cross, where it flowered for the first time in England in August 1807."
27. Nicholson in Woods and Forests (1884), p. 500.
28. The Sophora has withstood, without injury, the severest frosts in Perthshire. See pamphlet by Col. H.M. Drummond Hay, The Comparative Hardihood of Hardwooded Plants, from Observations made at Seggieden, Perthshire (1882).
29. Nicholson, in an excellent article on the Sophoras in Woods and Forests, July 30, 1884.
30. One of these is mentioned by Loudon, ii. 565, as being the largest near London, and measured in 1838 57 feet high and about 9 feet in girth.
31. This is said by Loudon (l.c.) to have been twenty years planted in 1844, though probably this is an error, as it was then 35 feet high.
32. Loudon says there were two trees in the garden, both 50 feet high, which had flowered occasionally.
33. There is a splendid Sophora in the grounds at Cobham Park, Kent, which I measured in 1905, and found to be 85 feet by 10 feet. There is also one in the Tilt Yard at Arundel Castle, 62 feet by 9 feet 6 inches.—(H.J.E.)