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A -

Prefix meaning without.

Abaxial

Located on the side away from the axis.

Achene

One-seeded, dry indehiscent fruit with a relatively thin wall in which the seed coat is not fused to the ovary wall.

Acuminate

Gradually tapering to a sharp point; point is drawn out.

Acute

Sharply pointed, but less tapering than acuminate; angle 90o or less.

Adaxial Located on the side nearest the axis.

Adhere

To stick to.

Adherent

Sticking or clinging.

Adnate

Fusion of unlike parts (e.g., fusion of palea to the caryopsis in Bromus).

Adventitious roots

Roots developing from basal culms, nodes, or some structure other than the seed.

Adventive

A term used to denote an exotic species that has become established from chance or accidental seeding.

Aggregate

Clustered or forming a group with objects in close proximity.

Alternate

Located singly at each node. An arrangement of parts, e.g. leaves, placed at different heights along an axis.

Annual

Completing life cycle from seed to maturity to death within one year or one season.

Anther

Pollen bearing portion of the stamen.

Antrorse

Directed upward or forward toward the apex; the opposite of retrorse.

Apex

Uppermost tip of a structure.

Apices

Plural of apex.

Apical

Located at the tip.

Apiculate

Ending in a short, flexible point.

Appendage

A secondary part or a projecting part.

Appressed

Lying against an organ in the direction of the apex.

Aristate

Provided with a short awn or bristle from the apex, edge or back of an organ.

Aromatic

Having an odor, fragrant or otherwise; bearing volatile essential oils.

Articulate

Jointed; a node for natural separation.

Ascending

Sloping or rising obliquely upward.

Asexual

Without sex; sexless; not involving gametes.

Asymmetrical

Not having planes which divide the structure into mirror-image halves.

Attenuate

Gradually narrowing to a pointed apex or base; sharper than acute.

Auricle

A finger-like appendage or flange of tissue at the junction of the blade and sheath in some grasses. Holds the open sheath to the culm.

Autumnal

Growth form for late summer and fall (e.g. Dichanthelium).

Awn

The extension of the vein (nerve) of spikelet bracts beyond the leaf-like tissue.

Axil

The upper angle between an organ (branch) and its axis.

Axillary

Occurring in an axil.

Axis

The central stem(s) of an inflorescence, particularly of a panicle.