Onobroma

Five species. 0. glaucum is a hardy annual, and O. ar-borescens, a green-house shrub, the others hardy herbaceous. Seed, cuttings-, or divisions. Common soil.

Onobrychis

Sainffoin. Twenty-threespecies. Hardy herbaceous. Seed. Chalky loam.

Onoclea

Two species. Hardy herbaceous. Seed and division. Sandy loam and peat.

Ononis

Thirty-seven species. Mostly hardy annuals and shrubby plants. Seed or cuttings. Loam.

Onosma

Sixteen species. Hardy herbaceous, except the stove O. triner-vum. Seed. Rich chalkv loam.

Onosmodium

Two species. Hardy herbaceous. Seed. Rich light loam.

Ophiopogon

Three species.

Half-hardy herbaceous. Division. Sandy loam and peat.

Ophioxylon

Ophioxylon serpentinum. Stove evergreen shrub. Cuttings. Sandy loam and peat.

Ophrys

Ten species. Hardy and half-hardy orchids. Seed. Chalky loam and peat.

Oplotheca

Two species.

O.florodana is hardy herbaceous, increased by division. 0. interrupta is a stove biennial, by seed. Both require loam and peat.

Opuntia

Eighty-seven species. Stove cacti, except 0. fragilis and O. missouriensis, which are hardy; and the half-hardies, O. media, 0. polyacantha, and 0. vulgar-is. Slips, slightly dried; sandy peat.

Orange

Citrus aurantium. See Citrus.

Orbea

Twenty-three species. Stove evergreen shrubs. Cuttingsslight-ly dried; sandy loam and lime rubbish.

Orchis

Thirty species. Chiefly hardy orchids. Seed. Chalky loam and peat.

Origanum

Marjoram. Eight species and some varieties. Hardy herbaceous and half-hardy evergreen shrubs. The former are increased by division; the latter by slips and cuttings. Sandy loam. See Marjoram.

Ormosia

Two species. Stove evergreen trees. Cuttings. Sandy peat.

Ornithidiu M

Two species. Stove epiphytes.

Ornithocephalus

Two species. Stove ep'phytes. Both these genera are increased by dividing the bulbs, and planting them in moss and wood.

Ornithogalum

Fifty-nine species. Hardy, half-hardy, and greenhouse bulbs. OtTsets. Sandy loam and peat.

Ornithoglossum

Two species. Green-house bulbs. Offsets. Sandy loam and peat.

Ornus

Flowering ash. Five species. Hardy deciduous trees. Seed and grafting, or buddingj on common ash. Light loam.

Orobus

Thirty-eight species. Hardy herbaceous, except O. saxatilis, which is annual, and O. Americanus, a green-house evergreen shrub. Seed and division. Light loam.

Ortegia

Two species. Hardy herbaceous. Seed and cuttings. Sandy loam and peat, well drained.

Orthotaenia

Orthotaenia, 0. resinella, turpentine moth; O. turionana, bud tor-trix. See Tortrix.

Orthrosanthus

Orthrosanthus multiflorus. Green-house herbaceous. Seed and division. Loam and peat.

Osage-Apple

Maculura.

Osbeckia

Six species. Stove shrubs, deciduous, and evergreen. Young cuttings. Sandy loam and peat.

Osier

Salix viminalis.

Osmites

Three species. Greenhouse evergreen shrubs. Cuttings. Light rich soil.

Osmunda

Seven species. Hardy ferns. Seed and division. Light rich loam.

Osteospermum

Thirteen species. Green-house evergreen shrubs. Cuttings. Light rich loam.