=Pelargonium=, _n._ From a Greek word meaning “a stork”; a member of
the Geranium Family, so called because of the beaked seed-pods.
=Petal=, _n._ From a Greek word meaning “a leaf”; one of the leaves of
a corolla.
=Phosphorus=, _n._ From a Greek word meaning “Lucifer, the morning
star”; a solid substance which is luminous in the dark. It is found
in composition in the bodies of animals and plants.
=Pioneer=, _n._ L. _pes_, a foot; in military terms, one of a company
of foot soldiers who march before an army with implements to clear
the way. Hence, whoever or whatever leads or prepares the way for
others coming after.
=Pistil=, _n._ L. _pistillum_, a pestle; the seed-bearing organ of a
flower, composed generally of three parts, ovary, style, and stigma,
and called pistil because of its shape, which often resembles a
pestle.
=Plant cells=, _n._ The cells of which plants are built up.
=Pollen=, _n._ L. _pollen_, fine flour; the dust or grains of
fertilizing material found in the anthers of flowers.
=Pollen cells=, _n._ The grains of pollen; each grain is a separate
cell.
=Polypetalous=, _a._ From two Greek words meaning “many” and “leaf.”
Said of a flower having two or more separate petals.
=Potash=, _n._ A combination of potassium, carbon, and oxygen. Potash
in various forms is found in all plants.
=Potassium=, _n._ A substance found in combination with other things
in the earth’s crust, and in the form of potash, an important factor
in the substance of plants and animals.
=Potato=, _n._ One of the edible tubers of the potato plant. The
potato is a swollen underground stem, the eyes being the nodes. The
potato contains a large amount of starch and is a valuable food. The
potato plant is a native of the Andes. It was taken to England from
Virginia in 1856.
=Prickles=, _n._ A.-S. _prica_, a sharp point; small, sharp-pointed
growths from the bark of plants.
=Primitive=, _a._ L. _primus_, first; pertaining to the beginning or
origin of a thing. In botany, beginning to take form, applied to an
organ or structure that is just beginning to assume form.
=Primus=, _n._ L. _primus_, first; a name given in this book to a
suppositional plant.
=Probing=, _n._ L. _probare_, to test, examine; examining by means of
a long, pointed instrument or probe. The bee or butterfly probes for
nectar with its long tongue.
=Protean=, _a._ Pertaining to Proteus; readily assuming different
shapes.
=Proteus=, _n._ In classical mythology, a sea god who had the power of
assuming different shapes. He could become a serpent or a cloud or a
bull or anything he chose to become.
=Protoplasm=, _n._ From two words meaning “first” and “form.” A
substance resembling the white of an egg in appearance, composed of
carbon, hydrogen, oxygen, nitrogen, sulphur, and phosphorus. It is
the foundation of all living forms.
=Protoplasmic=, _a._ Consisting of protoplasm.