BBC Gardeners' World

Labellum

The lip-like lower petal of an orchid flower, which is distinct from the others both in form and patterning. Serves as a platform for pollinating insects.

Lacerate

Of a leaf having torn or ragged edges.

Laciniate

Of a leaf or flower whose edges are jagged or fringed.

Lanceolate

To be shaped like a lance, usually referring to a long leaf that's broad at the middle.

Lanuginous

To be covered in a woolly down.

Larva

Refers to the post-embryonic stage in the development of an insect, before its metamorphosis into an adult. Examples are a caterpillar, grub or maggot. The larval stage is generally the most destructive period in the insect life cycle.

Lateral

A bud arising in the leaf axil at a node in the stem, which will develop into a side shoot.

Lax

Being loose, relaxed, widely spaced.

Leaching

The washing out, usually by rain, of soluble (and some insoluble) minerals from the soil. Because some substances leach faster than others, this may cause a chemical imbalance in the soil, which, in turn, may have a detrimental effect on plants. Commonly a problem with pot plants.

Leader

1) The tip of the main stem of a plant.

2) A main stem from which laterals arise.