Arcuate. Moderately curved.
Areolate. Marked out into small spaces, reticulate.
Aril. An appendage growing at or about the hilum of a seed.
Arillate. Having an aril.
Articulate. Jointed; having a node or joint.
Ascending. Rising somewhat obliquely, or curving upward. Ascending ovule, one that is attached above the base of the ovary and is directed upward.
Assurgent. Ascending.
Attenuate. Slenderly tapering, becoming very narrow.
Auricle. An ear-shaped appendage.
Auriculate. Furnished with auricles.