Achene (achaenium). A dry and indehiscent fruit, especially one with a thin pericarp.
Acuminate (acuminatus). Narrowed at the top and drawn out into a point.
Acute (acutus). Sharply pointed, but not drawn out.
Adelphous (adelphus). United in bundles, e.g., diadelphous = united in two bundles.
Adherent (adhaerens). Slightly united to an organ of another kind, usually to a part of another whorl.
Adnate (adnatus). Closely united with an organ of another kind, usually with a part of another whorl. Adnate anthers have their halves attached through their whole length to the filament.
Aërial (aëreus). Growing above the surface of the earth or water.
Aestivation (aestivatio). Praefloration, i.e., the arrangement of the perianth-leaves in the bud.
Albumen (albumen). The nutritive tissue (endosperm or perisperm) in which the embryo is more or less immersed.
Alternate (alternus). Placed between two parts; or inserted one on each node.