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Deripations. Pielea is the Greek name of the elm. It is derived from ptao, to fly, in allusion to the winged seed-vessels of this tree.

Generic Characters. Polygamous. Sepals 3–6, commonly 4, small. Petals much longer than the sepals,

spreading. Stamens alternate with and longer than the petals ; filaments thickened below and hairy on the inside ; in the fertile flowers very short and with sterile anthers. Ovary of 2 united carpels, placed on a convex torus; ovules 2 in each carpel, situated one above the other; styles short, united, or none; stigmas 2. Fruit a 2-celled samara, turgid in the centre, the margin expanded into a broad, orbicular membranaceous and reticulated wing. Seeds oblong, solitary in each cell. Leaves pinnately 3- (rarely 5-) foliate, with pellucid dots, the lateral leaflets inequilateral. Flowers whitish, cymose; cymes corymbed or panicled.— Torrey and Gray, Flora.

HE genus Ptelea embraces at least five species, four of which are indigenous to North America, and one to Cochin-China. The Ptelea monophylla, having simple, ovate, lanceolate leaves, is a native of Carolina, and grows to the height of four feet. The Ptelea pentandra and podocarpa are indigenous to Mexico, and

grow to a height of six to ten feet. The Ptelea ovata is a simpleleaved species, native of Cochin-China. The other species, and the only one that has been cultivated with success, or has attained much size, is the Ptelea trifoliata, and as it appears by its history, well deserves a place in collections, both on account of the singularity of its leaves and fruit, and the general beauty of the tree.

Ptelea trifoliata,
THE THREE-LEAFLETED-LEAVED PTELEA.

Synonymes.

Ptelea trifoliata,

Linnæus, Species Plantarum.
DE CANDOLLE, Prodromus.
Don, Miller's Dictionary.
Loudon, Arboretum Britannicum.
TORREY AND GRAY, Flora of North America.
FRANCE.
GERMANY.
ITALY.
BRITAIN AND ANGLO-AMERICA.

Orme de Samarie à trois feuilles,
Dreyblättrige Lederblume,
Ptelea,
Shrubby Trefoil, Tree Trefoil,

Engravings. Loudon, Arboretum Britannicum, v., pl. 59; and the figures below. Specific Characters. Leaf of three leaflets that are ovate acute, the middle one much tapered towards the base. Flowers in corymbs, usually tetrandrous.-De Candolle, Prodromus.

Description.

T

THE Ptelea trifoliata, in its

natural habitat, usually
grows to a height of six or

eight feet; but, when cultivated under favourable circumstances, it sometimes attains an elevation of forty feet and upwards. When the plant is pruned up with a single stem, it forms a handsome low tree, with a hemispherical head; but it is more frequently cultivated as a large shrub, with numerous stems proceeding from the same basal point. The leaflets are sessile, ovate, mostly acuminate, obscurely crenulate, the terminal one cuneiform, and attenuate at the base. The flowers, which appear in June and July, are of a greenish-white, grow in corymbose clusters, and have a disagreeable odour. They are succeeded by flattened winged capsules, somewhat resembling those of the elm; whence the French name orme.

Varieties. The varieties which have come under the notice of botanists are as follows:

1. P. T. PENTAPHYLLA, Munch. Five-leaflet-leaved Shrubby Trefoil. This variety can generally be distinguished in having five leaflets.

2. P. T. PUBESCENS, Pursh. Pubescent-leaflet-leaved Shrubby Trefoil. This variety is described as having its branchlets, petioles, and lower surface of its leaves clothed with a soft tomentose pubescence, even when old.

Geography, History, Soc. This species is found in moist, shady hedges, and on the borders of woods among rocks, from Lake Ontario to Florida, and as far west as Kentucky and Texas. It was originally sent to England by Banister, and plants of it were raised by Bishop Compton, at Fulham; but they were lost, and the species was re-introduced from Carolina by Catesby, in 1724. Being hardy, and of easy culture, in any common soil, this tree is not uncommon in the collections of Europe, and it well deserves a place there, as well as in those of the United States, both on account of the beauty of its leaves and fruit, and its general appearance.

The largest tree of this species, existing in Britain, and probably on the globe, is at Gordon Castle, in Bamffshire, Scotland. In 1835, it had attained the height of forty-five feet, with a trunk fifteen inches in diameter, and an ambitus or extent of branches of twenty-seven feet. It was grown in a loamy soil and in a sheltered situation.

In France, at Paris, in the Jardin des Plantes, there is another tree of this species, which attained the height of thirty-seven feet in sixty years after planting, with a head forty feet in diameter.

In Saxony, at Wörlitz, there is also a tree of this species, which attained the height of twenty-five feet in forty-five years after planting; and another tree of the variety Ptelea trifoliata pentaphylla, that reached the height of fifteen feet at thirty-four years planted.

Genus AILANTUS, Desf.

Xanthoxylaceæ

Syst. Nat.

Monæcia Polygamia.

Sysl. Lin.

Synonymes.

Ailantus, Ailanthus, Rhus,

OF AUTHORS.
Aylante
, Aylanthe, Verne du Japon, An- }France.

,
Götterbaum,

GERMANY.
Ailanto,

ITALY AND MOLUCCA ISLANDS.
Tong-yen-tsao, Tchean-theum,

China.
Ailanto, Ailantus,

BRITAIN AND ANGLO-AMERICA. Derivations. The word Ailantus (sometimes improperly written Ailanthus) was given to this genus by Desfontaines, who formed it from the Molucca name, ailanto. For a long time this tree was considered as a species of rhus, whence the French name, Verne. Angik or Angika, it is said, signifies the Tree of Heaven; hence the German name, Golierbaum, Tree of the Gods. Generic Characters. Male Flower. Calyx, 1-leafed, 5-parted, very small. Corolla, 5-petals, acute,

convolute at the base. Stamina, filaments 10, compressed, the length of the corolla.—FEMALE FlowER. Calyx, as in the male. Pistils, germs 3–5. Styles lateral. Capsules compressed. Seeds solitary, and lens-shaped. Bisexual flowers as in the above.

MONG before this genus was rightly named and its characters well

understood, one of its species was cultivated in the gardens of Europe and America, and was thought to be a kind of sumach; but as the tree, in general, bore only male flowers, much doubt and many conjectures were entertained, until it was accurately

described by Desfontaines, in 1786. There are several species in this genus, all natives of China, India, or the adjacent islands, but none are very hardy except the Ailantus glandulosa, indigenous to the northern prov. inces of China, and cultivated as an ornamental tree in nearly every country of the civilized globe.

[graphic]

Ailantus glandulosa,
THE GLANDULOUS-LEAVED AILANTUS.

Synonymes.

Ailantus glandulosa,
Ailantus procera,
Aylante glanduleux, Tilou,
Drüsiger Götterbaum,
Ailanto, Albero di Paradiso,
Ailantus, Tree of Heaven,

DESFONTAINES, Actes, etc., Paris, 1786.
DE CANDOLLE, Prodromus.
LOUDON, Arboretum Britannicum.
SALISBURY, Prodromus.
FRANCE.
GERMANY.
Italy.
BRITAIN AND ANGLO-AMERICA.

Engravings. L'Héritier, Stirpes, pl. 84 ; Du Hamel, Traité des Arbres et Arbustes, i., pl. 35; Loudon, Arboretum Britannicum, i., figure 159, et v., pl. 60; and the res below. Specific Characters. Leaves impari-pinnate ; the leaflets coarsely toothed at the base ; the teeth glandulous on the under side.—De Candolle, Prodromus.

Description.

[graphic]

HE Ailantus glan-
dulosa is a decid-
uous tree of the
first rank, grow-

ing to a height of

Why sixty feet and upwards. Its straight, erect, column-like trunk, from two to three feet in diameter, its gigantic boughs and shoots, clothed with large, pendulous leaves, give it a noble appearance, and seem to justify the oriental appellation, “Tree of Heaven.The leaves are from one and a half to six feet in length, pinnated, with an odd one, and having leaflets with coarse, glandular teeth near the base. On the first approach of frost, the leaflets begin to fall, without having previously shown much change of colour, displaying, in this respect, a striking difference from the leaves of most species of rhus, to which those of this tree bear a general resemblance. The flowers, which appear in June and July, occur in rather large, compact panicles, of a whitish-green colour, and exhale a disagreeable odour.' The keys, or fruit, resemble those of the ash, but are much smaller and more numerous. In some years, the tree is said to bear only male flowers; and L'Héritier states that only twice in ten years it bore both male and female blossoms at the same time, in France. In his time, it had produced fruit in the Jardin des Plantes, at Paris, and in the botanic garden at Leyden; but in both cases it was immature. It has since, however, produced perfect fruit, from which plants have been raised. It has also ripened seeds at White Knight's, near Reading, in England. At Philadelphia and New York, the seeds of this tree ripen freely in October, and plants are raised from them in abundance.

Geography and History. The Ailantus glandulosa is a native of the northern provinces of China, more particularly in the neighbourhood of Pekin. Mr. Loudon states that seeds were first sent to England, to the Royal Society of London,

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