P-R

Palmately compound:   A compound leaf with three or more leaflets radiating from a common point like fingers from a palm.

Panicle:  A compound inflorescence in which the main axis is branched and may support spikes, racemes, or corymbs.  Example: garden phlox (Phlox paniculata).

Pappus:  In members of the aster family, a reduced calyx that may be comprised of hairs or bristles.

Pedicel:  The stalk of a flower.

Peltate:  Refers to a leaf having a leafstalk that is attached in the center, giving the leaf an umbrella-like appearance.

Perfect:  A flower that contains both the male (stamen) and female (pistil) parts.

Petals: The inner layer of floral parts, often (but not always) brightly colored.

Petiole: The stalk of the leaf.

Petiolule: The stalk of the leaflet.

Phyllary: The bract-like structures found subtending the head (inflorescence) in plants in the aster family.

Pinnately compound:  A compound leaf with leaflets arranged on opposite sides of a common rachis (stalk).

Pistil: the female part of a flower; comprised of a stigma, style and ovary.

Pith:  The tissue in the center of a stem.

Pollen: Grains containing the male genetic material.  They are produced in the anthers.

Pubescent: Having hair.

Pulvinus: An enlargement of the base of the petiole.

Raceme:  A simple (unbranched) inflorescence with the flowers along the main axis on stalks).

Rachis:  The central axis (stalk) of a compound leaf.

Ray floret:  A tubular flower with a strap-like corolla found in members of the Aster family.  The structure thought of as a petal on a daisy is actually a ray floret.

Rhizome: A thickened, underground stem, usually with a horizontal orientation.

Rosette: Leaves radiating from a crown or center and usually at or close to the ground.