Acantholimon Glumaceum _(Prickly Thrift)_.--This is a frame evergreen perennial, thriving in any light, rich soil. It can be increased by dividing the roots. In May it puts forth its rose-coloured flowers. Height, 3 in. Acanthus.--A coarse, yet stately hardy perennial, which has large ornamental foliage, and flowers in August. It is not particular as to soil or situation, but free space should be given it. Will grow from seed sown from March to midsummer, or in August or September in a sheltered situation. Will also bear dividing. Height, 3 ft. Acer (_Maple_).--Very vigorous plants, suitable when young for pots, and afterwards for the shrubbery. The A. Negundo Variegata has silvery variegated leaves, which contrast effectively with dark foliage, Campestre Colchicum Rubrum, with its bright crimson palmate leaves, is very ornamental, as is also Negundo Californicum Aurem, with its golden-yellow foliage. The Maple grows best in a sandy loam. It may be increased by cuttings planted in a shaded situation, or by layers, but the choice varieties are best raised from seed sown as soon as it is ripe. Achillea Ptarmica (_Sneezewort_).--A pure white hardy perennial which blooms in August. The dried leaves, powdered, produce sneezing. Any soil. Best increased by rooted off-sets. Flowers from July to September. Height, 1-1/2 ft. Achimenes.--Fine plants, suitable for the greenhouse, sitting-room, or hanging baskets. Plant six tubers in a 5-in. pot, with their growing ends inclining to the centre and the roots to the edge of the pot, and cover them an inch deep with a compost of peat, loam, and leaf-mould, or a light, sandy soil. Keep them well supplied with liquid manure while in a growing state. Height, 6 in. to 2-1/2 ft. Aconite (_Monk's-Hood or Wolf's-Bane_).--Very pretty and very hardy, and succeeds under the shade of trees; but being very poisonous should not be grown where there are children. Increased by division or by seeds. Flowers June to July. Height, 4 ft. (_See also_ "Winter Aconites.") Acorus (_Sweet Flag)._--A hardy bog plant, having an abundance of light-coloured evergreen foliage. It will grow in any wet soil. Height, 2 ft. Acroclinium.--Daisy-like everlastings. Half-hardy annuals suitable for cutting during summer, and for winter bouquets. Sow in pots in February or March, cover lightly with fine soil, plunge the pot in gentle heat, place a square of glass on the top, and gradually harden off. Seed may also be sown in the open during May or in autumn for early flowering. Height, 1 ft. Acrophyllum Verticillatum.--A greenhouse evergreen shrub. It will grow in any soil, and may be increased by cuttings of half-ripened wood. March is its flowering season. Height, 3 ft.