pollen. The dust or grains contained in the anther, which, falling on the stigma, grows and fertilizes the forming ovules.
pollination. The transfer of pollen from the anther to the stigma. The transfer may be accomplished by wind, insects, birds, water (in the case of water plants), or by the natural falling of the pollen.
polypetalous (“many-petaled”). Said of a corolla with the petals not united.
polysepalous (“many-sepaled”). Said of a calyx with sepals not united.
pome. An apple-like or pear-like or quince-like fruit, with a five-carpeled or en-carpeled “core.”
proterandrous. Said of a flower when the anthers mature in advance of the pistils in the same flower.
proterogynous. Said of a flower when its pistils mature before its anthers.
prothallus (“first thallus”). The minute leaf-like body or organ produced by the germination of a spore, in ferns and allied plants. It bears the sex organs.
protoplasm. The living matter in plants. It is the living part of the cells, usually in a semi-fluid, translucent state.
pseud-annual. A plant that is apparently annual, but which is carried over winter by a bulb, tuber, or similar body; as potato, onion.