Gazania Splendens.—­A showy greenhouse plant.  It may be planted in the open in warm positions, but will require protecting in winter.  Grow it in peat and loam.  Cuttings will strike if placed in sand under glass.  It flowers in July.  Height, 1 ft.

Genethyllis.—­Greenhouse evergreen shrubs which thrive best in sandy loam and peat.  Cuttings of the young wood planted in the same soil and plunged in heat will take root.  Their flowering season is in August.  Height, 3 ft.

Genista (Broom).—­G.  Canariense is an exceedingly ornamental and free-flowering greenhouse shrub.  It should be planted in a mixture of loam, peat, and sand.  Young cuttings inserted in sand under a glass take root readily.  It blooms in June.  Height, 2 ft.  Hardy species of Genista may be placed in the front of shrubberies.  They are increased by seeds or by layers.

Gentians.—­The herbaceous kinds do best in a light, rich soil, such as loam and peat mixed with vegetable mould.  The annuals are raised from seed sown as soon as it is ripe; if left till spring before it is sown it will probably not come up till the second year.  The perennials are increased by dividing the roots.  Both of the latter kinds do best in a dry, sandy soil.  Gentiana Acaulis, or Gentianella, is very suitable for edgings, or for rock-work; it is an evergreen creeper, and bears large trumpet-shaped flowers of rich ultramarine blue.  All the Gentians need plenty of free air, and some of them moisture at the roots.  Bloom in July.  Height, 4 in. to 2 ft.

Geranium Argentium(Silvery Crane’s-Bill).—­This hardy perennial alpine is very effective on rock-work, especially in front of dark stones; but provision must be made for its long tap roots.  A rich, deep loam suits it well.  Its seeds germinate freely when sown in peat and sand.  Flowers are borne from May to July.  Height, 6 in.

Geraniums.—­Take cuttings in July or August, and let them he to partially dry for twenty-four hours before planting.  When rooted pot them off in 60’s, and keep them under glass during the winter at a temperature of 55 degrees.  If the cuttings are taken in September put three or four slips in a 48-size pot.  In the spring they should be re-potted singly and hardened off as early as possible.  A suitable soil for them is made by mixing two parts of good turfy loam, one of leaf-mould, one of well-decomposed cow-dung, and a good proportion of silver sand.  Bone dust is an excellent addition to the soil.  Old plants stripped of their leaves may be packed in sand during the winter, and re-potted in spring.

Gerardia.—­These hardy perennials form pyramidal bushes bearing Pentstemon-like flowers, thickly set and varying in colour from light pink to dark purple.  A peat soil suits them best.  They may be propagated by cuttings placed under glass, but are best grown from seed.  July is their flowering season.  Height, 1 ft. to 2 ft.

German Seeds.—­These require to be sown in a cold frame in seed-pans, in the greenhouse, or under a handglass, in good, rich compost, composed of old turf, leaf-mould, some well-rotted manure, and silver sand.  The seeds should be sown thinly and watered sparingly.  Sow early in April, and transplant in the middle or end of May in rich soil.  Water occasionally with weak liquid manure.