=Areca= (Cabbage Palm). _Palmæ._ Increased by seeds, which should be sown in a compost of loam, peat, and leaf soil, in equal parts, with a liberal addition of sand, and placed in a moist and gentle heat. =Arenaria= (Sandwort). _Caryophylleæ._ Increased by seeds, division or cuttings; the last placed under a hand-glass will root freely. Seeds should be sown in spring in a cold-frame. The best time to divide the plant is early spring, or during July and August. =Aretia.= See Androsace. =Argania.= _Sapotaceæ._ Increased by layers and cuttings. The latter require a propagating-frame. Both should be made in autumn and spring, and in a moderately heated greenhouse. =Argemone.= _Papaveraceæ._ Increased by seeds, which may be sown out-doors in spring; those of the rarer species in a hot-bed. =Argyreia= (Silver-weed). _Convolvulaceæ._ Propagated by cuttings, which will do well in sand, with a hand-glass over them, in a little bottom heat. =Argyrochæta.= See Parthenium. =Argyroxyphium.= _Compositæ._ Propagated by seeds. =Arisarum.= _Aroideæ._ Propagated in spring by seeds or divisions of the root. =Aristea.= _Irideæ._ Increased by seeds and divisions. =Aristolochia= (Birthwort). _Aristolochiaceæ._ Propagated by seeds and layers, which are not very satisfactory. Cuttings root freely in sand, under a bell-glass with bottom heat. The seeds must be fresh. =Aristotelia.= _Tiliaceæ._ Propagated by layers, or by ripened cuttings, which root freely if placed under a hand-glass. =Armeria= (Thrift, Sea Pink). _Plumbagineæ._ Increased by seeds sown in spring, in pots of sandy soil, and placed in a cold-frame; by division, separate pieces being planted as cuttings under hand-glasses. =Arnatto.= See Bixa. =Arnebia.= _Boragineæ._ Increased by seeds. Cuttings of the strong shoots should be inserted in pots of sandy soil, and placed in gentle heat. =Arnica.= _Compositæ._ Propagated by seeds sown in a cold-frame in spring, and by divisions, which should be made in spring. =Aronicum.= See Doronicum. =Arracacha.= _Umbelliferæ._ Increased by divisions of the roots. =Arrow-root.= See Calathea. =Arrhostoxylum.= See Ruellia. =Artabotrys.= _Anonaceæ._ Propagated by seeds; and by cuttings of ripened wood, placed in early spring in sand under a frame, with bottom heat. =Artanema.= _Scrophulariaceæ._ Increased readily by seeds and cuttings. =Artanthe.= See Piper. =Artemisia= (Mugwort, Southernwood, Wormwood). _Compositæ._ The annuals by seeds; the herbaceous ones, by dividing at the root; the shrubby kinds by cuttings. =Arthropodium.= _Liliaceæ._ Increased freely by seeds and by divisions. =Arthrostemma.= _Melastomaceæ._