Gesneria.—­Handsome greenhouse perennials.  They thrive in any light, rich soil.  Cuttings will strike readily either in sand or soil if placed under glass in heat.  They may also be raised from seed sown in a temperature of 75 degrees in March or April.  They flower in October.  Height, 18 in.

Geum.—­Very handsome hardy perennials.  They grow well in any light, rich, loamy soil, and may be increased either by seeds or by dividing the roots.  G. Coccineum is extremely pretty.  Flower in July.  Height, 18 in.

Gherkins.—­Sow the seed the first week in April in small pots, and cover it lightly with fine soil.  Plunge the pots in a hotbed covered with a frame.  When grown to nice little plants, remove them to a cold frame to harden, and plant them out on a warm border towards the end of May.  When the fruit begins to form, give liquid manure twice a week.  For pickling they must be cut while small.

Gilia.—­Extremely pretty and free-flowering hardy annuals, deserving of a place in every garden.  They are very suitable for small beds.  They should be sown in the open early in spring.  G. Tricolour may be sown in autumn.  Bloom in July.  Height, 1 ft.

Gillenia Trifoliata.—­The Three-Leaved Gillenia is a hardy herbaceous perennial which is very useful as a cut flower for the decoration of vases, etc.  It should be grown in large clumps, delights in a deep, moist soil and partial shade, and may be propagated by dividing the roots early in spring.  It lasts in bloom from June to August.  Height, 1 ft.

Gladiolus.—­Dig the ground out to a depth of 1 ft. or 15 in.; put in a layer of leaf-mould or rotted manure, and then 4 or 5 in. of earth mixed with sand; insert the bulbs (6 in. from the surface and 9 in. apart), cover them with 1 in. of sand, and fill up with earth.  In frosty weather cover with a thick layer of litter.  Give plenty of water when they begin to throw up their flower-stems.  They may be planted at any time between December and the end of March.  If planted late in the season, a depth of 3 or 4 in. is enough.  The roots must be kept dry in winter.  They are increased by off-sets, taken when the bulbs are removed from the ground after the leaves have turned yellow.  These should be planted at once in well-drained earth.  If early flowers are required, plant the old bulbs in pots (three to six bulbs being placed in a 5-in. pot) any time between December and March.  Give them frame culture up to the second week in May, when they may be transferred to the border.  The flowers are invaluable for vase decoration.

Glaucium Flavum Tricolor (Hardy Horn Poppy).—­The large, brilliant, orange-red flowers of this plant are very effective in the border, and the bloom is continuous during the greater part of the summer.  The seed is rather slow to germinate, but when sown in the open ground in autumn, it blooms from June to August; when sown in early spring it flowers from July to September.  Height, 2 ft.