Two of the three species which form the subject of this article are not
only highly ornamental, but also valuable timber trees. Until recently
they were considered to belong to the genus Planera, which, however,
consists of but a single New World species; now, they properly
constitute a distinct genus, viz., Zelkova, which differs materially
from the true Planer tree in the structure of the fruit, etc. Z.
crenata, from the Caucasus, and Z. acuminata, from Japan, are quick
growing, handsome trees, with smooth bark not unlike that of beech or
hornbeam; it is only when the trees are old that the bark is cast off in
rather large sized plates, as is the case with the planes. The habit of
both is somewhat peculiar; in Z. crenata especially there is a decided
tendency for all the main branches to be given off from one point;
these, too, do not spread, as for instance do those of the elm or beech,
but each forms an acute angle with the center of the tree. The trunks
are more columnar than those of almost all other hardy trees. Their
distinct and graceful habit renders them wonderfully well adapted for
planting for effect, either singly or in groups. The flowers, like those
of the elm, are produced before the leaves are developed; in color they
are greenish brown, and smell like those of the elder. It does not
appear that fruits have yet been ripened in England. All the Zelkowas
are easily propagated by layers or by grafting on the common elm.
[Illustration: YOUNG ZELKOWA TREE (21 FEET HIGH)]
_Zelkcova crenata_--The Caucasian Zelkowa is a native of the country
lying between the Black and the Caspian Sea between latitudes 35° and
47° of the north of Persia and Georgia. According to Loudon, it was
introduced to this country in 1760, and it appears to have been planted
both at Kew and Syon at about that date. A very full account of the
history, etc., of the Zelkowa, from which Loudon largely quotes, was
presented to the French Academy of Science by Michaux the younger, who
speaks highly of the value of the tree. In this he is fully corroborated
by Mirbel and Desfontaine, on whom devolved the duty of reporting on
this memoir. They say that it attains a size equal to that of the
largest trees of French forests, and recommend its being largely
planted. They particularly mention its suitability for roadside avenues,
and affirm that its leaves are never devoured by caterpillars, and that
the stems are not subject, to the canker which frequently ruins the elm.
The name Orme de Siberie, which is or was commonly applied to Zelkova
crenata in French books and gardens, is doubly wrong, for the tree is
neither an elm nor is it native of Siberia. In 1782 Michaux, the father
of the author of the paper above mentioned, undertook, under the
auspices, of a Monsieur (afterward Louis XVIII.), a journey into Persia,
in order to make botanical researches.
[Illustration: FOLIAGE OF A YOUNG ZELKOWA TREE, WITH FLOWERS AND FRUIT.]
"Having left Ispahan, in order to explore the province of Ghilan, he
found this tree in the forests which he traversed before arriving
at Recht, a town situated on the Caspian Sea. In this town he had
opportunities of remarking the use made of the wood, and of judging how
highly it was appreciated by the inhabitants." The first tree introduced
into Europe appears to have been planted by M. Lemonnier, Professor of
Botany in the Jardin des Plautes, etc., in his garden near Versailles.
This garden was destroyed in 1820, and the dimensions of the tree
when it was cut down were as follows: Height 70 feet, trunk 7 feet in
circumference at 5 feet from the ground. The bole of the trunk was 20
feet in length and of nearly uniform thickness; and the proportion of
heart-wood to sap-wood was about three quarters of its diameter. This
tree was about fifty years old, but was still in a growing state and in
vigorous health. The oldest tree existing in France at the time of the
publication of Loudon's great work, was one in the Jardin des Plantes,
which in 1831 was about 60 feet high. It was planted in 1786 (when a
sucker of four years old), about the same time as the limes which form
the grand avenue called the Allee de Buffon. "There is, however, a much
larger Zelkowa on an estate of M. le Comte de Dijon, an enthusiastic
planter of exotic trees, at Podenas, near Nerac, in the department of
the Lot et Garonne. This fine tree was planted in 1789, and on the 20th
of January, 1831. it measured nearly 80 feet high, and the trunk was
nearly 3 feet in diameter at 3 feet from the ground." A drawing of this
tree, made by the count in the autumn of that year, was lent to Loudon
by Michaux, and the engraving prepared from that sketch (on a scale of 1
inch to 12 feet) is herewith reproduced. At Kew the largest tree is one
near the herbarium (a larger one had to be cut down when the herbarium
was enlarged some years ago, and a section of the trunk is exhibited
in Museum No. 3). Its present dimensions are: height, 62 feet;
circumference of stem at 1 foot from the ground, 9 feet 8 inches; ditto
at ground level, 10 feet; Height of stem from ground to branches, 7
feet; diameter of head, 46 feet. The general habit of the tree is quite
that as represented in the engraving of the specimen at Podenas. The
measurements of the large tree at Syon House were, in 1834, according to
Loudon: Height, 54 feet; circumference of of stem, 6 feet 9 inches;
and diameter of head, 34 feet; the present dimensions, for which I am
indebted to Mr. Woodbridge, are: Height, 76 feet; girth of trunk at 2½
feet from ground, 10 feet; spread of branches, 36 feet.
[Illustration: FLOWERS AND FRUIT OF ZELKOVA CRENATA (_Planera
Richardi_).]
IDENTIFICATION.--Zelkova crenata, Spach in Ann. des Sc. nat. 2d ser. 15,
p. 358. D. C. Prodromus, xvii., 165 Rhamnus ulmoides, Güldenst. It.,
p. 313. R carpinifolius, Pall. Fl Rossica, 2 p. 24, tab. 10. Ulmus
polygama, L C. Richard in Mem. Acad. des Sciences de Paris, ann. 1781.
Planera Richardi, Michx. Fl. bor. Amer. 2, p. 248; C.A. Meyer, Enumer.
Causas. Casp., n. 354; Dunal in Bulletin Soc. cent d'Agricult. de
l'Herault. ann. 1841, 299, 303, et ann. 1843, 225, 236. Loudon, Arbor,
et Frut. Brit., vol. 3, p. 1409. Planera crenata, Desf. Cat. Hort. Paris
et hortul, fere omnium. Michaux fil. Mem. sur le Zelkowa, 1831. Planera
carpinifolia, Watson, Dend. Brit., t. 106. Koch Dendrologie, zweit
theil, sweit. Abtheil. p. 425.
[Illustration: ZELKOWA TREE AT PODENAS
Showing peculiar habit of branching. In old trees the effect is very
remarkable in winter as at Oxford, Versailles (_Petit Trianon_) and
Syon.]
_Var pendula_ (the weeping Zelkowa).--This is a form of which I do not
know the origin or history. It is simply a weeping variety of the common
Zelkowa. I first saw it in the Isleworth Nurseries of Messrs. C. Lee &
Son, and a specimen presented by them to Kew for the aboretum is now
growing freely. I suspect that the Zelkova crenata var. repens of M.
Lavallee's "Aboretum Segrezianum" and the Planera repens of foreign
catalogues generally are identical with the variety now mentioned under
the name it bears in the establishment of Messrs. Lee & Son.
[Illustration: FOLIAGE OF A FULL-GROWN ZELKOWA TREE.]
_Z. acuminata_ is one of the most useful and valuable of Japanese timber
trees. It was found near Yeddo by the late Mr. John Gould Veitch, and
was sent out by the firm of Messrs. J. Veitch & Sons. Maximowicz also
found the tree in Japan, and introduced it to the Imperial Botanic
Gardens of St. Petersburg, from whence both seeds and plants were
liberally distributed. In the _Gardeners' Chronicle_ for 1862 Dr.
Lindley writes as follows: "A noble deciduous tree, discovered near
Yeddo by Mr. J. G. Veitch, 90 feet to 100 feet in height, with a
remarkably straight stem. In aspect it resembles an elm. We understand
that a plank in the Exotic Nursery, where it has been raised, measures 3
feet 3 inches across. Mr. Veitch informs us that it is one of the most
useful timber trees in Japan. Its long, taper-pointed leaves, with
coarse, very sharp serratures, appear to distinguish it satisfactorily
from the P. Richardi of the northwest of Asia." There seems to be no
doubt as to the perfect hardiness of the Japanese Zelkowa in Britain,
and it is decidedly well worth growing as an ornamental tree apart
from its probable value as a timber producer. A correspondent in the
periodical just mentioned writes, in 1873, p. 1142, under the signature
of "C.P.": "At Stewkley Grange it does fairly well; better than most
other trees. In a very exposed situation it grew 3 feet 5 inches last
year, and was 14 feet 5 inches high when I measured it in November;
girth at ground, 8¾ inches; at 3 feet, 5 inches." The leaves vary in
size a good deal on the short twiggy branches, being from 3 inches to
3½ inches in length and 1¼ inches to 1½ inches in width, while those on
vigorous shoots attain a length of 5 inches, with a width of about half
the length. They are slightly hairy on both surfaces. The long acuminate
points, the sharper serratures, the more numerous nerves (nine to
fourteen in number), and the more papery texture distinguish Z.
acuminata easily from its Caucasian relative, Z. crenata. The foliage,
too, seems to be retained on the trees in autumn longer than that of the
species just named; in color it is a dull green above and a brighter
glossy green beneath. The timber is very valuable, being exceedingly
hard and capable of a very fine polish. In Japan it is used in the
construction of houses, ships, and in high class cabinet work. In case
99, Museum No. 1 at Kew, there is a selection of small useful and
ornamental articles made in Japan of Keyaki wood. Those manufactured
from ornamental Keyaki (which is simply gnarled stems or roots, or
pieces cut tangentially), and coated with the transparent lacquer for
which the Japanese an so famous, are particularly handsome. In the
museum library is also a book, the Japanese title of which is given
below--"Handbook of Useful Woods," by E. Kinch. Professor at the
Imperial College of Agriculture, at Tokio, Japan. This work contains
transverse and longitudinal sections of one hundred Japanese woods, and
numbers 45 and 46 represent Z. acuminata. It would be worth the while of
those who are interested in the introduction and cultivation of timber
trees in temperate climates to procure Kinch's handbook.
IDENTIFICATION.--Zelkova acuminata, D.C. Prodr., xvii., 166; Z. Keaki,
Maxim. Mel. biol. vol. ix, p. 21. Planera acuminata, Lindl. in Gard.
Chron. 1862, 428; Regel, "Gartenflora" 1863, p. 56. P Japonica, Miq.
ann. Mus. Ludg Bat iii., 66; Kinch. Yuyo Mokuzai Shoran, 45, 46. P.
Keaki, Koch Dendrol. zweit. theil zweit Abtheil, 427. P. dentata
japonica, Hort. P. Kaki, Hort.
[Illustration: FLOWERING TWIG OF PLANERA GMELINI.]
_Z. cretica_ is a pretty, small foliaged tree, from 15 to 20 feet in
height. The ovate crenate leaves, which measure from an inch or even
less, to one inch and a half in length by about half the length in
breadth, are leathery, dark green above, grayish above. They are hairy
on both surfaces, the underside being most densely clothed, and the
twigs, too, are thickly covered with short grayish hairs. This species,
which is a native of Crete, is not at present in the Kew collection; its
name, however, if given in M. Lavallee's catalogue, "Enumeration des
Arbres et Arbris Cultives à Segrez" (Seine-et-Oise).
[Illustration: OLD SPECIMEN OF ZELKOWA TREE IN SUMMER FOLIAGE,
CONCEALING FORM OF BRANCHING.]
IDENTIFICATION.--Zelkova cretica. Spach in Suit à Buff, ii, p. 121.
Ulmus Abelicea, Sibth & Sm. Prod. Fl., Graeca, i., p. 172. Planera
Abelicea Roem. & Schltz. Syst., vi. p. 304; Planch, in Ann. des Sc. Nat.
1848, p. 282. Abelicea cretica, Smith in Trans. Linn. Sov., ix., 126.
I have seen no specimens of the Zelkova stipulacea of Franchet and
Savatier's "Enumeratio Plantarum Japonicarum," vol. ii., p. 489, and as
that seems to have been described from somewhat insufficient material,
and, moreover, does not appear to be in cultivation, I passed it over as
a doubtful plant.