ACHILLEA (named after Achilles, who is said to have first discovered the medicinal qualities of this plant). Including Ptarmica. Milfoil. ORD. Compositæ. A large genus (about fifty species), containing numerous hardy, border and alpine plants. Flower-heads small, corymbose; involucral scales oblong, often with a shrivelled appearance; receptacle with membranous scales, resembling chaff; ray florets few, sometimes rather large and showy; pappus none. Leaves ternate, simple or compound. All the species are easily cultivated in ordinary garden soil. A. Eupatorium and other large-growing kinds are well suited for borders or groups, whilst the alpine section should be planted on the rockery. A great number of species, although excellent for naturalising in rough shrubberies, are totally unfitted for garden culture. Propagated, during spring, by root divisions, cuttings, and seeds.
A. ægyptiaca (Egyptian).* fl.-heads rich bright yellow, in closely packed terminal corymbs, which are from 2in. to 4in. across. Summer. l. pinnate; leaflets obtusely lanceolate, serrate, silvery white, 6in. to 8in. long. h. 1½ft. to 2½ft. Levant, 1640. Handsome perennial, thriving best in a warm position.
A. Ageratum (ageratum-leaved).* fl.-heads pure white, large, borne singly on stalks about 6in. or 8in. high. Summer. l. narrow, arranged in a dense silvery rosette, the margins prettily crimped. Greece. A pretty alpine, of compact habit.
A. asplenifolia (asplenium-leaved).* fl.-heads rose-coloured, small, in a compound corymb. June to September. l. lower ones stalked, pinnatifid, lobes pinnate; upper ones pinnate. h. 18in. North America, 1803.
A. atrata (black-cupped).* fl.-heads white. August. l. in a rosette, pinnatifid, deep shining green. Austria, 1596. A pretty alpine.
A. aurea (golden-flowered).* fl.-heads golden yellow, borne singly on stems 18in. high. Summer and autumn. l. larger than in A. ageratifolia, with which species it is sometimes confused. Levant, 1739. Habit tufted. Requires a warm position.
FIG. 11. ACHILLEA CLAVENNæ, showing Habit and detached Flower-heads.
A. Clavennæ (Clavenna's).* fl.-heads white, in neat and compact heads. Spring and summer. l. bipinnatifid; segments linear, obtuse, slightly denticulated at the apex. h. 10in. Austria, 1656. A very neat and pretty species, having dwarf tufted habit and a hoary appearance. See Fig. 11.
A. decolorans (staining). fl.-heads whitish yellow. July. l. undivided. h. 1ft. Native country unknown. 1798.
FIG. 12. ACHILLEA EUPATORIUM, showing Habit and detached Flower-head.
A. Eupatorium (fern-leaved).* fl.-heads brilliant yellow, in dense convex, compound corymbs, which are often 5in. across, lasting two months in full beauty. June to September. l. numerous, linear, pinnate, lobed and serrated, hairy, rough. h. 4ft. to 5ft. Caucasus, 1803. This noble plant should be grown at the back of the border, and kept neatly staked. SYN. A. filipendula. See Fig. 12.
A. filipendula (dropwort-leaved). Synonymous with A. Eupatorium.
A. Herba-rota (Herba-rota).* fl.-heads white, in lax corymbs, on slender stems. May. l. lanceolate, serrated. h. 6in. France, 1640. When touched, this pretty little plant gives off an agreeable aromatic perfume. To attain full beauty it requires sandy loam and a sunny position.
A. macrophylla (large-leaved). fl.-heads white. July. l. long and broad pinnate; leaflets horizontal. h. 3ft. Italy, 1810.
A. Millefolium roseum (rosy).* fl.-heads rose-coloured, in small ovoid heads, which are produced continuously for several months. l. strap-shaped; segments very narrow. h. 1ft. to 3ft. England. It is well worth growing, both as a border plant, and for cutting purposes.
A. mongolica (Mongolian). fl.-heads white. July. l. undivided. h. 1½ft. Siberia, 1818.
A. moschata (musky).* fl.-heads white, in lax corymbs. June. h. 6in. l. bright green, about 2in. long, pinnatifid. Italy, 1775. A pretty tufted alpine.
A. nana (dwarf). fl.-heads white. June to August. l. pinnate; leaflets horizontal. h. 6in. Italy, 1759. A rockery species.
A. odorata (sweet-scented). fl.-heads white, fragrant. June to August. l. bipinnate. h. 6in. Spain, 1729.
A. pectinata (comb-leaved).* fl.-heads white. June. l. bright green, about 2in. long, pinnatifid. Italy, 1775. A pretty tufted alpine.
A. Ptarmica flore-pleno (double sneezewort).* fl.-heads pure white, freely produced in terminal corymbs. All through the summer and autumn. l. lanceolate, serrulate. h. 1ft. to 2ft. England. This is one of the most useful white border perennials grown, increasing very readily. When out of flower the stems should be cut down to the surface.
A. santolinoides (lavender-cotton-like). fl.-heads white. July. l. pinnate; leaflets transverse. h. 1ft. Spain.
A. serrata (serrated).* fl.-heads clear white, large, in small corymbose clusters, forming a somewhat spreading panicle. Summer. l. white, with adpressed hairs, sessile, lanceolate, deeply serrated. h. 15in. Switzerland, 1686.
FIG. 13. ACHILLEA TOMENTOSA, showing Habit and detached Portion of Inflorescence.