GLOSSARY OF TERMS USED 235 
Persistent.—Remaining when other parts have fallen. 
Petal.—A segment of the corolla. 
Petaloid.—Of the sepals when they assume the characters of 
petals. 
Petiolate.—Having a leaf-stalk. 
Petiole.— Leaf-stalk. 
Phyllaries.—The bracts or scales in an involucre. 
Pilose.—With stiff but scattered hairs. 
Pinnate.—With leaflets arranged on either side of a common 
petiole. . 
Pinnatifid.—When the segments of a leaf are nearly divided 
down to the midrib, sometimes twice or thrice divided. 
Pistil.—The female part of a flower, composed of ovary and 
ovules, crowned by stigma and style (or more than one). 
Pistillate.—A female flower, in unisexual flowers, or one having 
no stamens. 
Pith,—The cellular central portion of a root, or stem, or branch, 
sometimes wanting. 
Placenta.—That part of the carpel from which the ovules spring. 
Plumule.—The ascending rudimentary shoot in the embryo. 
Pod.—A one-celled seed-vessel with two valves, or legume. 
Pollen.—The dust or contents of an anther, dry or granular, or 
combined in a mass and waxy (pollen-mass, as in orchids). 
Pollen-grain.—A pollen cell, or microspore. 
Pollen-sac.—A microsporangium in which the pollen-grains are 
developed. 
Pollination.—The process by which pollen is conveyed from the 
anthers to the stigma. 
Polygamous.—When male, female, and hermaphrodite flowers 
occur on the same plant, as in the Ash. 
Poly petalous.— With several distinct petals. 
Polysepalous.—With several distinct sepals. 
Pome.—A fleshy many-celled compound fruit, as in the Apple, 
where the ovary is inferior. 
Posterior.—The portion of the flower near the axis. 
Proterandrous.—When the anthers mature first. 
Proterogynous.— When the stigma matures first. 
Pubescent.—Downy, with closely appressed hairs. 
Punctate.—With minute pin-holes. 
Pungent.—Strong. 
Pyxis.—A capsule opening by a lid, as in Anagallis. 
