BBC Gardeners' World

Maggot

The common term for the larva of flies.

Magnesium

Metallic element essential in the production of chlorophyll in plants. Magnesium deficiency can stunt development, but may be combated by an annual application of foliar feed.

Maiden

1) A plant grown from seed or a newly rooted runner.

2) A young, reproductively immature tree in the first year following grafting.

Manganese

Metallic trace element that's an essential micro-nutrient for healthy plants.

Manure

Any bulky material supplying nutrients to the soil. May be derived from animals in the form of dung and farmyard waste, or from plants (see Green manures).

Marginal

Of the margins or edges of leaves, or of organs such as petals.

Mealybug

An insect that looks like a wood louse, but which is coated in a pale, waxy substance. It feeds on plant sap, and is best controlled by systemic insecticide.

Membranous

Like a membrane, being very thin, translucent or papery.

Mentum

In the structure of an orchid, it's the forward-jutting extension of the base of the column.

Microspecies

In taxonomy, the microspecies is the unit below species level.