BBC Gardeners' World

Raceme

An inflorescence on which individual flowers, on short stalks of their own, arise from a central, unbranched stem. Normally these flowers open from the base upward.

Rachis

The central axis that carries flowers or leaves.

Radical

1) Pertaining to the root.

2) Leaves growing from the base of a stem, rhizome or crown.

Recurved

Of foliage or flowerheads that curve or bend backwards.

Reflexed

See Recurved.

Remontant

A term used to describe plants that flower more than once in a season, eg, some rose varieties.

Reniform

A leaf that's kidney shaped. Usually attached to the petiole or leaf stalk at the middle of the inward curve of the leaf.

Repeat-flowering

See Remontant.

Replant disease

A problem that affects trees or shrubs when they've been planted in soil where a plant of the same species had been growing. It particularly applies to members of the Rosaceae family (roses, apples, cherries, plums). Symptoms include retarded development, poor growth and a general failure to thrive. If moved to fresh soil, plants invariably recover.

Resting period

The interval of time during which a plant is dormant. For most plants this occurs during the winter months.