PICEOUS: In botany, pitch-black; shiny brownish-black.
PILEATE: Having a pileus, or cap, like a mushroom.
PILEOLUS: A small pileus.
PILEUS: The expanded umbrella-like cap of a mushroom.
PILOSE: Covered with hair, especially with soft or fine hair.
PINCHING, PINCHING BACK, OR PINCH OUT: To remove the growing tip of a plant, with finger and thumb, to encourage the production of sideshoots or the formation of flower buds. Pinching out is also used when small side shoots are completely removed. This is done when single stems are desired, especially when training to form the "trunks" of standard (tree-form) specimens.
PINNA: One of the primary divisions or leaflets of a divided leaf or frond, such as in ferns and palms.
PINNATE: Resembling a feather in structure with the parts arranged on both sides of an axis; A compound leaf in which the leaflets grow in a row on each side of the midrib.
PINNATIFID: Cut or sectioned to form a feather shape, as the fronds of many ferns.
PINNATION: The state or condition of being pinnate.
PINNATISECT: Cut to the midrib in a pinnate manner.
PINNULATE: Having divided segments that are themselves further divided, as the leaves of some acacias.
PINNULE: A secondary pinna; one of the ultimate divisions of a doubly divided leaf.
PISTIL: The female part of a flower. A complete pistil consists of three parts: stigma, ovary, and style (when present).
PISTILLATE: Having a pistil; Having pistils but no functional stamens.
PISTILLINE: Relating or belonging to the pistil.
PISTILLODE: A rudimentary or vestigial pistil.
PITCHER: In botany, a specially adapted pitcher-shaped modification of the leaf of certain plants, such as Nepenthes and Sarracenia (Pitcher Plants).