Awl-shaped. Narrowed upward from the base to a slender or rigid point.
Awn. A bristle-shaped appendage.
Axil. The angle formed by a leaf or branch with the stem.
Axillary. Situated in an axil.
Axis. The central line of any organ or support of a group of organs; a stem, etc.
Baccate. Berry like; pulpy throughout.
Barbed. Furnished with rigid points or short bristles, usually reflexed like the barb of a fish-hook.
Barbellate. Finely barbed.
Barbulate. Finely bearded.