BBC Gardeners' World

Staminode

A sterile stamen.

Standard

1) A plant or shrub pruned and trained to grow into a tree-like form, with one trunk or stem that's 3-6ft long before branches appear. The practice is entirely aesthetic, and often used for roses. See Half standard.

2) The erect petals of the iris, as opposed to its drooping falls.

Stellate

Star shaped.

Sterile

1) Barren. Incapable of producing fruit, seeds or spores.

2) Aseptic, as in sand, vermiculite, perlite etc, which has been heat treated to remove all harmful living organisms.

Stigma

The area of a pistil that's receptive to pollen. It's essential for reproduction.

Stipule

A small, leaf-like outgrowth at the base of a petiole. Often found in pairs.

Stolon

A shoot which runs along or just below the ground which roots at the tip and produces a new plant. Differs from a runner which produces roots at the nodes along the length of the stem.

Stool

1) A clump of roots used in propagation.

2) A tree stump or an old root that produces new shoots.

Stooling

The practice of cutting a plant down to ground level to encourage new growth.

Stopping

A method of pruning whereby the plant's tip is removed to encourage the production of side shoots.