Mesembryanthemums (Ice Plants).—­These half-hardy, annual succulents have a bright green foliage covered with ice-like globules.  They must be raised in a greenhouse or on a hotbed, sowing the seed in April on sandy soil.  Prick the young plants out in May.  If grown in pots they thrive best in a light, sandy loam.  In the border they should occupy a hot and dry situation.  Keep the plants well watered until established, afterwards give a little liquid manure.  May be increased by cuttings taken in autumn.  Cuttings of the more succulent kinds should be allowed to dry a little after planting before giving them water.  A dry pit or frame is sufficient protection in the winter; they merely require to be kept from frost.  Flower in July.  Height, 1 ft.

Mespilus.—­For treatment, see “Medlars.”

Meum Athamanticum.—­A hardy perennial with graceful, feathery green foliage, but of no special beauty.  It is a native of our shores, will grow in any soil, blooms in July or August, and is freely propagated by seeds.  Height, 1-1/2 ft.

Michaelmas Daisies (Starworts).—­A numerous family of hardy herbaceous perennials.  Some few are very pretty, while others can only be ranked with wild flowers.  They thrive in any soil or position, but flourish best where there is a due proportion of sunshine.  They are easily raised from seed, sown early in spring, or may be increased by root-division either in the autumn, as soon as they have done flowering, or in the spring.  They vary in height from 1 ft. to 5 ft.

Michauxia Campanuloides.—­This is an attractive border biennial, bearing from March to June white campanula-like flowers tinged with purple, on erect stems.  It is not particular as to soil, but requires a southern position and protection in winter.  Propagated by seeds in the same way as other biennials.  Height, 4 ft.

Mignonette.—­For summer-flowering plants sow the seed in spring, and thin out to a distance of 9 in. apart.  To obtain bloom during the winter and spring successive sowings are necessary.  Let the first of these be made the second week in July in light, rich soil; pot off before frost sets in, plunge them in old tan or ashes, and cover with a frame facing the west.  Another sowing should be made about the middle of August, giving them the same treatment as the previous; and a third one in February, in gentle heat.  Height, 9 in. to 3 ft.  The Mignonette tree is produced by taking a vigorous plant of the spring sowing, and removing all the lower shoots in the autumn.  Pot it in good loam, and keep it in the greenhouse in a growing state, but removing all the flowers.  By the spring the stem will be woody.  Let the same treatment be given it the second year, and the third season it will have become a fine shrub.  It may be made to bloom during the winter by picking off the blossom in the summer and autumn.  Height, 3 ft.

Mildew.—­Syringe with a strong decoction of green leaves and tender branches of the elder-tree, or with a solution of nitre made in the proportion of 1 oz. of nitre to each gallon of water.  Another good remedy is to scatter sulphur over the leaves while the dew is upon them, afterwards giving them a syringing of clear water.