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.