POD: A dry fruit or seed vessel that bursts open when mature and is more or less elongated and cylindrical or flattened, as of the pea, bean, or catalpa.
PODZOLIZATION: The process by which soil is depleted of alkaline material and becomes more acidic.
POLLARD: A tree cut back nearly to the trunk in order to form a thick head of spreading branches, which are cut for basket-making and kindling. Poplars and Willows are often pollarded.
POLLEN: The dust-like particles on the anthers of a flower are pollen grains; these contain the male gametes. They must unite with the female gametes before fertile seeds can be produced.
POLLEN TUBE: This is the tube that develops from the wall of the pollen grain in seed plants, providing a passage way for the male gametophytes to reach the embryo sac for fertilization.
POLLINARIUM (pl. pollinaria): A functional unit in Orchid pollination that consists of two or more pollinia, stalk or stipe, and viscidium.
POLLINIUM (pl. pollinia): A mass of pollen grains.
POLLINATION: The transfer of pollen from the anther to the stigma of the same or a different flower to ensure fertilization of the ovules to produce seeds.
POLYADELPHOUS: Having the stamens united in three or more bundles.
POLYANDROUS: Having many stamens.
POLYCARPELLARY: Composed of several carpels
POLYCARPIC: Producing fruit many times or indefinitely; having a gynoecium forming two or more distinct ovaries or carpels.
POLYCOTYLEDON: A plant having more than two cotyledons or seed-leaves. This is usually the case with pines and most conifers.
POLYCOTYLEDONY: A variation in the number of cotyledons of a plant.
POLYGAMODIOECIOUS: Basically dioecious, but also having some bisexual flowers present in some or all plants.
POLYGAMOUS: Bearing both unisexual or bisexual flowers on the same plant or on plants of the same species.
POLYGYNOECIAL: Having a number of pistils joined together, as in aggregate fruits such as the raspberry.
POLYGYNOUS: Having many styles.
POLYMORPHIC: Occurring in several different forms, as leaves on the same plant that have different shapes.
POLYMORPHISM: The capability or tendency to have wide variation in form.
POLYMORPHOUS: Having or assuming many forms.
POLYPETALOUS: Having two or more separate petals.
POLYSPORANGIUM: A sporangium containing many spores.
POLYSTAMONOUS: Having many stamens; polyandrous.
POLYTOMOUS: Divided into more that two subordinate parts or branches; pinnatifid.
POLYTOMY: The state of being divided into more than two parts.
POMOLOGIST: A person who is experienced in pomology; a cultivator of fruit trees.
POMOLOGY: A department of knowledge that deals with fruits; a branch of gardening that deals with the cultivation of fruit trees or fruit-bearing shrubs.
PORE: A small opening, as in the surface of a leaf.
PORE SPACE: The total space within soils that isn't occupied by soil particles.
POROSTIY: The degree to which soil mass is permeated with pores or cavities.
POROUS SUBSOIL: A subsoil in which air between its particles allows the water to drain through easily.
POTASSIUM: An element used by plants for growth, often present in the soil but not in the right form to be absorbed by the plant's roots unless humus (decayed organic matter) is present.
POT-BOUND: Said of a plant having an overly extensive root system in a too-small container.
POT FEET: Small supports placed under pots and planters to raise them off the ground for better drainage and air circulation.