=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.
[Illustration: FIG. 13. ACHILLEA TOMENTOSA, showing Habit and detached Portion of Inflorescence.]
=A. tomentosa= (downy).* _fl.-heads_ bright yellow, in repeatedly compound corymbs. Summer. _l._ woolly, bipinnatifid; segments linear, acute. _h._ 8in. to 12in. Europe. One of the best yellow-flowered species for the rock garden, having a dense habit. See Fig. 13.
=A. umbellata= (umbel-flowered).* _fl.-heads_ white, six to eight in a simple umbel. June. _l._ regularly lobed; lobes obovate, entire; clothed with a dense, silvery pubescence, on which account the plant is chiefly cultivated. _h._ 4in. to 5in. Greece. A very pretty, dwarf rock plant.
=A. vallesiaca= (Vallesian). _fl.-heads_ white. June to August. _l._ pinnate; leaflets horizontal. _h._ 1ft. Switzerland, 1819.
=ACHIMENES= (from _cheimaino_, to suffer from cold; alluding to the general tenderness of the species). Including _Scheeria_. ORD. _Gesneraceæ_. A large genus of handsome, stove or warm greenhouse, branched, generally hairy, herbaceous perennials, with scaly, catkin-like stolons underground (see Fig. 14), and sometimes from the axils of the leaves. Corolla funnel-shaped; tube rather oblique, gibbous behind at the base; pedicels one-flowered, axillary, solitary or fasciculated, bracteated. Leaves opposite, or three in a whorl, serrated.
[Illustration: FIG. 14. ROOT OF THE ACHIMENE, showing Tubercles.]