Adventitious root

A root which arises from any part of a plant other than in the normal sequence of growth of the root system

Adventitious shoot

A shoot arising in a position other than the axil of a leaf or at the tip of a stem

Air pruning

The use of bottomless containers, or containers with holes in the sides, to arrest root development

Alien

A plant originally introduced from other areas

Alpine

A plant which is indigenous to the zone above the line at which trees cease to flourish and below the limits of perpetual snow (and by extension, a plant which will thrive in simulated alpine conditions

Alternate

(Leaves) borne singly at each node on opposite sides of the stem

Annual

A plant which grows from seed, flowers, fruits and dies within one year.

Anther

Pollen-bearing part of the stamen

Apical dominance

Of growth, the dominance of the terminal bud to the lateral buds

Aquatic plant

A non-woody plant suitable for growing within in shallow water or in saturated soil

Axil

Angle formed by a leaf or lateral branch with the stem, or that formed by a vein with the midrib.

Axillary

Produced in the axil