A
Aeration – Introducing air into the soil by making holes in it or pulling cores of soil out of it.
Aerification – The mechanical removal of soil cores.
Algae – Any of a group of chiefly aquatic lower plants without root, stem, or leaves, classified by color.
Aphids – Any of various small insects, such as the greenfly, that suck the juice of plants.
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Appressed – Lying close and flat against, as a bud against a twig.
Auricle – Ear-shaped appendage
Awnless – Without the beard or bristle-like appendage of the outer glume of numerous grasses.
Axillary – Springing from, or positioned in the angle formed by the upper side of a branch with the stem or trunk to which it is attached.