=Fertility=: the state of being fruitful. Land is said to be fertile when it produces well. =Fertilization=: the act which follows pollination and enables a flower to produce seed. =Fetlock=: the long-haired cushion on the back side of a horse's leg just above the hoof. =Fiber=: any fine, slender thread or threadlike substance, as the rootlets of plants or the lint of cotton. =Filter=: to purify a liquid, as water, by causing it to pass through some substance, as paper, cloth, screens, etc. =Formalin=: a forty per cent solution of a chemical known as formaldehyde. Formalin is used to kill fungi, bacteria, etc. =Formula=: a recipe for the making of a compound; for example, fertilizer or spraying compounds. =Fungicide=: a substance used to kill or prevent the growth of fungi; for example, Bordeaux Mixture or copper sulphate. =Fungous=: belonging to or caused by fungi. =Fungus= (plural =fungi=): a low kind of plant life lacking in green color. Molds and toadstools are examples. =Germ=: that from which anything springs. The term is often applied to any very small organism or living thing, particularly if it causes great effects such as disease, fermentation, etc. =Germinate=: to sprout. A seed germinates when it begins to grow. =Girdle=: to make a cut or groove around a limb or tree. =Glacier=: an immense field or stream of ice formed in the region of constant snow and moving slowly down a slope or valley. =Globule=: a small particle of matter shaped like a globe. =Glucose=: a kind of sugar very common in plants. The sugar from grapes, honey, etc. is glucose. That from the sugar cane is not. =Gluten=: a vegetable form of protein found in cereals. =Graft=: to place a living branch or stem on another living stem so that it may grow there. It insures the growth of the desired kind of plant. =Granule=: a little grain. =Gypsum=: land plaster. "=Head back=": to cut or prune a tree so as to form its head, that is, the place where the main trunk first gives off its branches. =Heredity=: the resemblance of offspring to parent. =Hibernating=: to pass the winter in a torpid or inactive state in close quarters. =Hock=: the joint in the hind leg of quadrupeds between the leg and the shank. It corresponds to the ankle in man. =Host=: the plant upon which a fungus or insect is preying. =Humus=: the portion of the soil caused by the decay of animal or vegetable matter. =Hybrid=: the result of breeding two different kinds of plants together. =Hydrogen=: a chemical element. It is present in water and in all living things. =Individual=: a single person, plant, animal, or thing of any kind. =Inoculate=: to give a disease by inserting the germ that causes it in a healthy being. =Insectivorous=: anything that eats insects. =Kainit=: salts of potash used in making fertilizers. =Kernel=: a single seed or grain, as a kernel of corn. =Kerosene emulsion=: see Appendix.