Ocreate. Having sheathing stipules.
Ochroleucous. Yellowish-white.
Officinal. Of the shops; used in medicine or the arts.
Oospore. The fertilized nucleus or germ-cell of the archegonium in Cryptogams, from which the new plant is directly developed.
Opaque. Dull; not smooth and shining.
Operculate. Furnished with a lid.
Operculum. A lid; the upper portion of a circumscissile capsule.
Orbicular. Circular.
Orthotropous (ovule or seed). Erect, with the orifice or micropyle at the apex.
Oval., Broadly elliptical.