P

Paddock

A smaller, fenced pasture, a subdivision or one of many subdivisions of a larger grazing area. Paddocks enable better control of the grazing of the pasture.

Palatability

The acceptability of a plant to the livestock grazing or consuming it. Given a choice, livestock will find one forage species or parts of the same forage more palatable than another.

Palmate

Divided or lobed. On palmate legume leaves, the leaflets arise from a common point, without a stalk. Examples include the leaves of alsike, kura, red and white clover.

Panicle

A multi-branched cluster of flowers, each with its own stalk. A panicle has a subdivision in addition to that of a raceme. The lower branches have longer stalks and open first. Bromegrass, fescue, bluegrass and oats have panicles.

Pathogens

Pathogens are infectious agents that can cause a disease or illness to its host.

Perennial Plant

A plant that persists for more than two years. For legumes and grasses commonly used for forage, the shoots are annual and regrow from the perennial crown in spring.

pH

Solutions may be acidic (below pH 7.0), neutral (pH = 7.0) or basic (pH above 7.0). Basic is the same as alkaline. The pH scale is logarithmic, e.g. a solution with an acidity of 5.0 is ten times more acidic than one with a pH of 6.0.

Photosensitization

An abnormal reaction or sensitization of the skin of an animal to sunlight due to a compound present in forage that has been eaten by the animal.

Photosynthesis

The process by which green plants use the energy from sunlight to produce carbohydrates from carbon dioxide and water.

Pinnate

A leaf arrangement on a compound leaf where the leaflets are on each side of a common axis. An odd pinnate leaf has a single leaflet at the tip, giving it an odd number of leaflets. On legumes with three leaflets, if the terminal leaflet has a stalk, it is a pinnate leaf arrangement. Alfalfa, sweet clover and cicer milkvetch have odd pinnate leaf arrangements.

Pod

The fruiting body of legumes. The pod is the shell that contains the seed or seeds.

Pollinator

An insect that transfers pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization of the flower for seed production. Insects are the most important pollinators of legumes. Grasses are commonly wind pollinated.

ppb

Parts per billion.

Prostrate

To lie flat on the ground.

Pubescent

Covered with hair.

Pure Live Seed (PLS)

The percentage of viable seed within a seed lot; calculated by multiplying the percent germination by the percent purity of the see lot. Using a Pure Live Seed calculation allows for forages to be seeded at proper rates to obtain a productive stand.

Purity

The percentage of the desired species in relation to the total quantity, including other species, weed seed, and foreign matter.