ARENARIA (from arena, sand; in which most of the species are found). Sandwort. ORD. Caryophyllaceæ. TRIBE Alsineæ. A very large genus of hardy herbaceous plants, consisting of about 150 species. It is distinguished by having generally three styles. The perennials only are worth growing; these are extremely pretty little alpine plants, and will thrive in any ordinary soil in exposed places; the rarer species may be grown in small pots, well drained, in a mixture of sand, loam, and leaf soil, or in well-drained crannies of the rockery. They may be increased by either division, seeds, or cuttings; the latter, placed under a hand-glass, will root freely. The best time to divide the plants is early spring, or July and August. Seeds should be sown in spring in a cold frame.
A. balearica (Balearic).* fl. white, sepals erect; peduncles elongated, one-flowered. March to August. l. very small, ovate, shining, rather fleshy, ciliated. h. 3in. Corsica, 1787. A pretty little creeper, one of the best plants for covering damp borders of the rockwork.
A. cæspitosa (tufted). Synonymous with A. verna cæspitosa.
A. ciliata (ciliated). fl. white, usually solitary; sepals ovate, acute, five to seven ribbed; petals obovate, twice as long as the sepals. July. l. ovate, or obovate, roughish, with a few hairs, one-nerved, and ciliated. Ireland. h. 6in. A thick, tufted, spreading, procumbent plant.
A. graminifolia (grass-leaved).* fl. white; panicle three-forked, hairy, loose; sepals very blunt, much shorter than the obovate petals. June. l. long, awl-shaped, filiform, scabrous on the margins from serratures. Stem erect, simple. h. 6in. to 9in. Caucasus, 1817.
A. grandiflora (large-flowered).* fl. white, usually solitary; peduncles very long, pubescent; sepals ovate, awned, three-nerved, smaller than the petals. June. l. awl-shaped, broadish, flat, three-nerved, ciliated, radical ones crowded. h. 3in. to 6in. France, 1783. A. g. biflora is a two-flowered, and A. g. triflora a three-flowered, variety.
A. laricifolia (Larch-leaved).* fl. white; sepals bluntish, triple nerved, hairy; petals twice as long as the sepals; stems ascending, one, three, or six flowered, somewhat scabrous; calyx cylindrical. June. l. awl-shaped, denticulately ciliated. h. 6in. Switzerland, 1816.
A. longifolia (long-leaved). fl. white; sepals ovate, obtuse, not half the length of the obovate petals; panicle three-forked, glabrous, crowded. June. l. awl-shaped, filiform, serrulated. Stem erect, simple. h. 6in. to 9in. Siberia, 1823.
A. montana (mountain). fl. large, white; peduncles terminal, very long, one-flowered; sepals lanceolate, acuminated, much shorter than the corolla. April. l. lanceolate-linear; sterile stems very long, procumbent. h. 3in. France and Spain, 1800.
A. peploides (Peplis-like). fl. white; sepals ovate, shorter than the oblong petals. May to July. l. ovate, light green, rather fleshy; branches procumbent, fleshy, deciduous. h. 3in. to 4in. Sea shores of Britain. SYN. Honckenya peploides.
A. purpurascens (purplish).* fl. purplish; pedicels tomentose, scarcely exceeding the leaves; sepals lanceolate, smooth, with shrivelled margins, longer than the corolla; branches two to three-flowered. May. l. ovate-lanceolate, acuminated, glabrous. Plant tufted, decumbent. h. 6in. Higher Pyrenees.
A. rotundifolia (round-leaved).* fl. white, solitary; petals roundish-ovate, longer than the sepals. July and August. l. about ¼in. across, roundish, ciliated, on spreading tufted branches. h. 4in. to 6in. Siberia.
A. tetraquetra (four-angled). fl. white, somewhat capitate; sepals stiff, acute, keeled, ciliated, almost equal in length to the corolla. August. l. ovate, keeled, recurved, edged, imbricated in four rows. Stem straight, pubescent. h. 3in. to 6in. France, 1731.
A. verna (spring-flowering). fl. small, white; sepals ovate, lanceolate, acuminated, with three remote equal ribs, longer than the obovate petals. May. l. awl-shaped, bluntish. Stems panicled, elongated. h. about 3in.
A. v. cæspitosa (turfy). A variety having very leafy stems. Calyces and peduncles smoothish. Europe. SYN. A. cæspitosa.
ARENGA (name of doubtful origin). SYN. Saguerus. ORD. Palmæ. An extremely useful and interesting palm. The medulla of the trunk is used as sago, and the saccharine juice forms excellent sugar. It requires a strong heat and rich mould. Propagated by seeds only.
A. saccharifera (sugar-bearing). fl. striped. June. h. 40ft. Moluccas, 1829.
AREOLATE. Divided into distinct angular spaces, or areolæ.
ARETHUSA (mythological: named after a nymph of Diana's, who was changed into a fountain; in allusion to the habit of the plants). ORD. Orchideæ. A small genus of very pretty, but rare, terrestrial orchids. They require a moist shady spot with a northern aspect, and thrive best in a compost of well-rotted manure and sphagnum. A mulching in winter, by way of protection, is needed.
A. bulbosa (bulbous).* fl. large, bright rose purple, solitary, sweet-scented, terminal; lip dilated, recurved, spreading towards the summit, bearded-crested down the face; scape one-leaved. May. l. linear, nerved. h. 8in. Carolina.
ARETIA. See [Androsace].
ARGANIA (from argam, its aboriginal name). ORD. Sapotaceæ. A very fine greenhouse evergreen tree, said by Don to flourish against a south wall, out of doors, with the protection of a mat in severe weather. It will thrive in ordinary garden soil. Increased by layers and cuttings in autumn and spring, the latter requiring a bell glass covering; both operations must be performed in a moderately heated greenhouse.
A. Sideroxylon (Iron-wood). fl., corolla greenish yellow, cup-shaped, five-parted, with ovate-lanceolate, sub-emarginate segments; lateral and axillary, scattered, crowded, sessile. fr. dotted with white, size of a plum, full of white, milky juice. July. l. lanceolate, entire, bluntish, glabrous, paler beneath; branches terminated by strong spines. h. 15ft. to 20ft. Morocco, 1711. As the specific name implies, the wood is excessively close and hard, so much so that it sinks in water. SYNS. Elæodendron Argan, Sideroxylon spinosum.