ACER, (from acer, hard or sharp; wood is extremely hard, and was formerly much used for making pikes and lances). Maple. ORD. Sapindaceæ. A genus comprised, for the most part, of handsome hardy deciduous shrubs, or trees, adapted for forming shrubberies, plantations, &c. Flowers greenish, except where mentioned. A. Pseudo-platanus is one of our most useful forest trees. Several of the species produce very useful timber; sugar is one of the constituent parts of the sap of all of them, and is obtained in large quantities from A. saccharinum, in North America. They all prefer a somewhat sheltered position. The most satisfactory soil is one free, deep, loamy, and well drained; the latter is especially desirable with some of the Japanese varieties. The varieties of A. japonicum, and palmatum are well worth growing in pots for conservatory decoration. Propagation: By seeds, sown either in autumn or spring, covering them not more than a ¼in. deep; the common varieties may be sown outside, while the rarer ones should be sown in a frame. By layers, and by grafting; the latter method is adopted with many of the rarer species and varieties, especially the variegated kinds; they are also readily increased by budding in summer.
A. austriacum (Austrian). Synonymous with A. campestre austriacum.
A. campestre (field).* Common Maple. fl. on erect racemes. May. fr. wings of fruit much divaricated. l. small, cordate, with five-toothed lobes. h. 20ft. Britain. A small tree with rough bark, full of deep fissures; wood often beautifully veined, when it is highly valued.
A. c. austriacum (Austrian).* fl. much larger than those of the species. fr. smooth. Lobes of leaves somewhat acuminated. SYN. A. austriacum.
A. c. collinum (hill-loving).* fl. smaller. fr. smooth. Lobes of leaves obtuse. France.
A. c. hebecarpum (downy-fruited).* fr. clothed with velvety pubescence.
FIG. 9. LEAF AND FLOWER SPIKE OF ACANTHUS SPINOSUS.
A. c. lævigatum (smooth-leaved). l. very smooth and shining.
A. c. nanum (dwarf). Dwarf habit.
A. c. tauricum (Taurian).* l. larger and less divided than in the species.
A. c. variegatum (variegated).* l. beautifully variegated with blotches and stripes of white or whitish yellow; very distinct.
A. circinatum (circinate).* fl. deep red, umbellate. April. l. seven to nine-lobed, serrulated. h. 5ft. to 6ft. North West America, 1827. A very beautiful species, having pendulous branches clothed with leaves, which change into a bright scarlet colour in the autumn.
A. creticum (Cretan). fl. on few-flowered erect corymbs. May. fr. smooth, with the wings hardly diverging. l. cuneated at the base, acutely three-lobed at the top. h. 4ft. Levant, 1752. Nearly evergreen.
A. dasycarpum (thick-fruited).* fl. conglomerate, on short pedicels, apetalous. April. l. truncate at the base, palmately five-lobed, with blunt recesses, and unequally and deeply-toothed lobes. h. 40ft. North America, 1725. SYNS. A. eriocarpon, A. tomentosum, A. glaucum, and A. virginianum.
A. Douglasii (Douglas). Synonymous with A. glabrum.
A. eriocarpon (hairy-fruited). Synonymous with A. dasycarpum.
A. Ginnala (Ginnalian).* fl. on compound, crowded, erect racemes. Amur River. This is generally classed as a variety of A. tartaricum, but its habit is much more graceful, and in this form the leaves are prettily cut and lobed, whilst the leafstalks and midrib are more deeply coloured.
A. glabrum (smooth).* fl. corymbose, on short two-leaved branchlets, greenish-yellow. June. l. roundish-cordate, deeply three to five-lobed, or partite; the lobes biserrate, of a light green. h. 15ft. to 30ft. North West America. SYNS. A. Douglasii, A. tripartitum.
A. glaucum (glaucous). Synonymous with A. dasycarpum.
A. heterophyllum (various-leaved).* fl. corymbose. May. l. small, ovate, entire, and three-lobed, slightly serrated, smooth. h. 4ft. Levant, 1759. An evergreen. SYN. A. sempervirens.
A. ibericum (Iberian). fl. corymbose. May. l. bluntly three-lobed; lobes with one or two teeth, lateral ones marked with the middle nerve to the insertion of the petiole. h. 20ft. Iberia, 1826.
A. japonicum (Japanese).* fl. deep purplish-red, large. April. l. many-lobed, in early spring very light green. h. 20ft. Japan, 1863. The varieties of this species, although not well fixed in many cases, rank amongst the most handsome of the deciduous small shrubs grown, but often change in character as they attain any considerable size. Plants from 1½ft. to 3ft. high are very useful in cool conservatories, and in the highly kept grounds surrounding the house.
A. laurifolium (laurel-leaved). Synonymous with A. oblongum.
A. Lobelii (Lobel's). l. very slightly heart-shaped, irregularly toothed, five-lobed; lobes more or less abruptly pointed.
A. macrophyllum (large-leaved).* fl. on erect, compound, racemes. May. l. digitately five-palmate, with roundish recesses; lobes somewhat three-lobed. h. 60ft. Northern California, 1812.
A. monspessulanum (Montpelier).* fl. on few-flowered corymbs, erect. May. l. cordate, three-lobed; lobes almost or quite entire, equal. h. 10ft. to 20ft. South Europe, 1739.
A. montanum (mountain). fl. on compound, erect racemes. May. l. cordate, three or slightly five-lobed, unequally and coarsely serrated. h. 18ft. Canada, 1750. SYN. A. spicatum.
A. Negundo. See Negundo fraxinifolium.
A. oblongum (oblong). fl. on compound racemes, pale yellow. February. l. oblong-lanceolate, acuminated, quite entire. h. 20ft. Nepaul, 1824. SYN. A. laurifolium.
A. obtusifolium (obtuse-leaved). fl. drooping, corymbose. May. l. rounded, bluntly three-lobed, crenately serrulate, about the length of the petioles. h. 15ft. Crete.
A. Opalus (Opalus). A synonym of A. opulifolium.
A. opulifolium (Guelder-rose-leaved).* fl. on nearly sessile corymbs. May. Ovaries and fruit smooth. l. cordate, five-lobed; lobes obtuse, bluntly and coarsely toothed. h. 8ft. France, 1823. SYN. A. Opalus.
A. o. obtusatum (bluntish).* A larger, strong growing, round-headed tree, with dark green leaves, which are covered with a whitish or rusty tomentum on the under surface.
A. palmatum (palmate-leaved).* fl. on five to seven-flowered umbels. May. l. palmately divided into five to seven lobes beyond the middle; lobes oblong, acuminated, serrated. h. 20ft. Japan, 1820.
A. p. atropurpureum (dark purple).* A vigorous handsome plant, with bold dark purple foliage. Japan.
A. p. crispum (crispy or waved).* l. green, with red stalked, convoluted edges. Japan, 1871. Very distinct, and like a miniature Lombardy poplar in habit of growth.
A. p. dissectum (finely-divided).* fl. red, on terminal-stalked racemes, five to six-flowered. May. l. nine to ten parted; lobes oblong, acuminated, deeply serrated. h. 30ft. Japan, 1845.
A. p. ornatum (beautiful).* Very ornamental, having finely cut deep red leaves, with lighter midribs. Japan, 1871. This variety is also known as dissectum.
A. p. palmatifidum (palmatifid).* l. very finely palmately divided, the lobes cut down quite to the midrib, of a beautiful light green colour. 1875.
A. p. reticulatum (netted).* l. palmately seven-lobed; lobes unequal, sharply serrate, emerald green, with dark green veins. Japan, 1875. A very elegant variety, with slender branches.
A. p. roseo-marginatum (rose-margined).* l. freely divided, the lobes deeply cut, light green, margined with rose. Japan, 1874. A very distinct and charming variety.
A. p. sanguineum (blood-red).* l. deeply five-lobed, the lobes serrated, of a deep reddish-crimson colour, much brighter than the variety atropurpureum. 1874. This presents a very striking contrast to the last.
A. p. septemlobum (seven-lobed).* fl. purplish, on numerous flowered umbels. Spring. l. varying much, from palmately five-lobed, with toothed undivided lobes, to deeply seven to nine-lobed, with more or less finely cut divisions. Japan, 1864. There are numerous beautiful forms of this variety.
There are many varieties of this much varying species, but we have only mentioned those best known; many are only known by their native names, and there is some doubt as to their distinctive characteristics. They are all extremely handsome.
A. pennsylvanicum (Pennsylvanian).* fl. in long drooping, simple racemes. May. l. cordate, three-lobed, acuminated, finely and acutely serrated. h. 20ft. Trunk elegantly striped with white lines. North America, 1755. SYN. A. striatum.
A. pictum (painted).* fl. corymbose, stalked. l. five to seven-lobed; lobes triangular or oblong, entire, acuminated. h. 15ft. to 20ft. Temperate Asia, 1840. A. p. connivens (converging), A. p. marmoratum (spotted), A. p. rubrum (red), and A. p. variegatum (variegated), are varieties differing principally in the colouring of the leaves. All are very desirable.
A. platanoides (plane-like).* The Norway Maple. fl. on nearly erect stalked corymbs. May, June. l. cordate, smooth, five-lobed; lobes acuminated, with a few coarse acute teeth. h. 50ft. Europe, 1683. A very ornamental hardy tree, growing with great rapidity when young. It prefers a deep, well-drained soil.
A. p. aureo variegatum (golden-variegated).* l. variegated with yellow. Europe, 1383. This, to retain the variegation, requires to be propagated by budding or grafting. The same remarks are equally applicable to the other varieties.
A. p. laciniatum (cut-leaved).* l. deeply and variously cut, green and yellow.
A. p. Schwedleri (Schwedler's).* l. very large, deep bronzy-red. A vigorous grower, and most effective.
A. p. variegatum (variegated).* l. variegated with white. There are several other varieties, but of less importance than the foregoing.
A. Pseudo-platanus (Mock-plane tree).* Sycamore. fl. on rather compound pendulous racemes. May. l. cordate, with five acuminated unequally-toothed lobes. h. 30ft. to 60ft. Europe. There are few deciduous trees so well adapted for standing singly in rough exposed situations. A deep, soft, dry soil is most suitable for it, but it will grow in soils of very opposite qualities.
A. P. albo variegata (white-variegated).* A very beautiful form, in spring especially. l. white and green.
A. P. flavo variegata (yellow-variegated). l. variegated with yellow.
A. P. longifolia (long-leaved).* l. more deeply cut, and the petioles much longer than in the species.
A. P. purpureum (purple).* l. purple underneath. The tree, when slightly ruffled by the wind, alternately appearing clothed in purple and pale green. Numerous other varieties of more or less excellence are grown.
A. rubrum (red).* Scarlet Maple. fl. scarlet, handsome, conglomerate, corymbose. l. cordate at the base, deeply and unequally toothed, palmately five-lobed, with acute recesses. Branches and fruit also scarlet. h. 20ft. Canada, 1656. A variety with leaves splashed with yellow is rare. An excellent species, thriving well in damp, swampy situations, and is commonly increased by layers.
A. rufinerve (red-nerved).* "The leaves vary both in size and outline, from 2½in. to 4in. each way; three to five-lobed, with irregularly toothed margins, glabrous above, but with reddish hairs along the nerves beneath. The young branches are conspicuous on account of the bluish-grey glaucescence with which they are covered."
A. r. albo-limbatum (white-margined).* differs only from the species in having a very distinct white margin—not always constant. Japan, 1869.
A. saccharinum (Sugar Maple).* fl. yellow, on drooping corymbs, on short peduncles; pedicels pilose. April. l. cordate, smooth, palmately five-lobed; lobes accuminated, sinuately toothed. h. 40ft. N. America, 1735.
A. s. nigrum (blackish).* fl. on sessile corymbs, nodding. April, May. l. cordate, with the recess closed; palmately five-lobed. h. 40ft. North America, 1812.
A. Semenovi (Semenov's).* A slender and graceful species, with leaves closely resembling those of A. Ginnala, but smaller. Turkestan, 1879.
A. sempervirens (evergreen). Synonymous with A. heterophyllum.
A. spicatum (spiked). Synonymous with A. montanum.
A. striatum (striated). Synonymous with A. pennsylvanicum.
A. tartaricum (Tartarian).* fl. white, on crowded, erect, compound racemes. May. l. more or less cordate, acuminated, serrated, with obsolete lobes. h. 20ft. 1759. This species is one of the first to expand its leaves in spring.
A. tomentosum (tomentose). Synonymous with A. dasycarpum.
A. tripartitum (three-parted). Synonymous with A. glabrum.
A. Van Volxemii (Van Volxem's). fl. not known in England. l. palmately three to five-lobed, very large, light green above, silvery and quite glabrous beneath. Caucasus, 1877. Distinct and fine.
A. villosum (hairy). fl. fragrant, on lateral racemes. April. Buds, fruit, and young leaves, silky, villous. l. cordate, five-lobed, villous beneath as well as the petioles; lobes ovate acute. h. 50ft. Himalaya, at high elevations. Not hardy.
A. virginianum (Virginian). Synonymous with A. dasycarpum.
ACERACEÆ. An order of very ornamental hardy trees, of which the sycamore and maple are well-known representatives.
ACERAS (from a, without, and keras, a horn; the lip having no spur). ORD. Orchidaceæ. An interesting genus of terrestrial orchids. Calyx of three ovate, equal, converging sepals; petals two, narrow, oblong; lip spurless, much longer than the calyx, narrow, oblong, with four linear lobes. The most interesting species is the native one. Indigenous to dry, chalky pastures in the south-east of England, and it will only thrive in similar soils when grown in gardens. Propagated by careful divisions of tubers only.
