=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. Q. =Quartus=, _n._ L. _quartus_, fourth; the name given in this book to a suppositional plant. =Quintus=, _n._ L. _quintus_, fifth; the name given in this book to a suppositional plant. R. =Rain=, _n._ A.-S. _regn_, rain; the water falling in drops through the atmosphere. Water rises as vapor from the moist earth and the sea; it is then condensed by coming in contact with the cold upper air, and falls to the earth as rain. =Reproduced=, _pp._ L. _re_, again, _producere_, to produce, to bring forth; produced again, having formed new plants or animals from those already existing. =Retrogressed=, _pp._ Went backward. =Retrogression=, _n._ L. _retro_, backward, _gradi_, to go; the act of going backward. =Rhea=, _n._ In classical mythology, the wife of Saturn and mother of Jupiter. =Ribs=, _n._ The bones that form the framework of the chest in the higher animals; the timbers that form the framework of a ship; the stiff fibres that form the framework of a leaf. =Robinson Crusoe=, _n._ A story written by Daniel Defoe and published in 1719. The adventures of Robinson are said to have been suggested by the life of Alexander Selkirk, who was shipwrecked and lived for four years on the desert island of Juan Fernandez. =Root=, _n._ The part of a plant that usually grows down into the soil, fixing the plant and absorbing nutriment. =Root cap=, _n._ The hard cap which covers and protects the growing tip of a root. =Root hairs=, _n._ The fine filaments growing from the skin of young roots that absorb the nutriment for plants. =Rubythroat=, _n._ The name of the North American humming bird, so called because of the bright red feathers on its throat. S. =Salamander=, _n._ A kind of lizard, formerly supposed to be able to live in the fire. =Salt=, _n._ One of the most important substances in the world. It is necessary to the existence of animals and is one of the constituents of many plants. =Sap=, _n._ The juice of plants. It is to them what the blood is to animals. =Saturn=, _n._ In classical mythology, the father of Jupiter. =Scales=, _n._ A.-S. _scealu_, a scale, husk; in botany, a small, rudimentary leaf, scale-like in form. Scales cover the leaf buds and sometimes the flower buds; they also constitute some bulbs. =Scape=, _n._ L. _scapus_, shaft, stalk; the long, leafless peduncle which starts from the ground and bears flowers at the top, as in the hyacinth.