234 THE STORY OF PLANT LIFE 
Oblique.—With the sides unequal. 
Obovate.—The inverse of ovate (gq. v.). 
Obovoid.—The inverse of ovoid (g. v.). 
Obtuse.—Blunt, making an angle greater than a right-angle (¢/. 
acute, g. v.). 
Offshoot.—Stems which strike a different direction from the 
main stem. 
Opposite.—When similar organs are given off directly bit Ri 
or on each side, of a common stem, etc., as of leaves. 
Orbicular.—Nearly round. 
Oval.—Elliptic, rounded at each end, twice as long as broad, as a 
rule. 
Ovary.—The base of the pistil which encloses the ovules, and 
later, when fertilised, forms the fruit. 
Ovate.—Egg-shaped, broader below the middle, flat. 
Ovoid.—Egg-shaped, but solid. 
Ovule.—An immature seed, equivalent to the megasporangia in 
Cryptogams, and which encloses the embryo-sac, or megaspore. 
Ovum.—The unfertilised egg-cell (with the synergide forming 
the egg-apparatus formed of nuclei in the embryo-sac). 
Panicle.—A loose cluster of flowers, branched. 
Papilionaceous.—The form of flower found in the Pea, butterfly- 
like, with a vexillum or standard, two alz, and the carina. 
Papilla.—A wart-like projection. 
Pappus.—The hairy limb of the calyx, equivalent to sepals. 
Patelliform.—Disc-shaped, with a rim. 
Pedicel.—An ultimate flower stalk. 
Pedicellate.—Borne on a pedicel, not sessile. 
Peduncle.—A main flower stalk, as often in a single-flowered 
plant. 
Peltate.—Buckler-shaped. 
Perennial.—A plant whose green parts, or leaves, die down to the 
stem base, but are renewed each year, or merely deciduous, as in trees, 
Perianth.—The whorls of a flower, of calyx and corolla, applied 
when these are not distinct. 
Pericarp.—The seed-vessel with the calyx adherent to it, or wall 
of an ovary that has become fertilised to form fruit. 
Perigynous.—When the corolla or stamens are on the rim, and 
the carpels below but still called superior. 
