BBC Gardeners' World

Spike

An inflorescence on a single, upright stem.

Spine

1) A sharply pointed outgrowth from a stem.

2) A prickle, as seen on holly.

Spit

The depth of a spade or fork - usually 10-12in/25-30cm.

Spore

A simple reproductive cell of non-flowering plants, eg, ferns and fungi. It's highly capable of surviving in unfavourable conditions.

Sport

A spontaneous genetic mutation, whether naturally occurring or induced. A plant that varies from the norm.

Springtail

One of a number of species belonging to the order Collembola. These insect-like creatures feed on living or decaying vegetation, and can be a nuisance in greenhouses. They can be controlled using insecticide.

Spur

1) A tubular projection located at the base of a petal, which often contains nectar.

2) A large lateral root, or the branch of a root.

Staking

The practice of supporting young or fragile plants, by loosely attaching them to canes or stakes driven into the ground.

Stalk

The common name for the stem of a flower or leaf. Specifically, the correct term for a flower stalk is pedicel, and for a leaf stalk the term is petiole.

Stamen

The male reproductive organ of a plant that produces pollen, and comprises anther and filament.