valuable plant food are in the air; but, strange to say, most plants
cannot use it directly from the air, but must take it in other forms, as
nitrates, etc. The legumes are an exception, as they can use atmospheric
nitrogen.

=Available plant food=: food in such condition that plants can use it.

=Bacteria=: a name applied to a number of kinds of very small living
beings, some beneficial, some harmful, some disease-producing. They
average about one twenty-thousandth of an inch in length.

=Balanced ration=: a ration made up of the proper amounts of
carbohydrates, fats, and protein, as explained in text. Such a ration
avoids all waste of food.

=Biennial=: a plant that produces seed during the second year of its
existence and then dies.

=Blight=: a diseased condition in plants in which the whole or a part of
a plant withers or dries up.

=Bluestone=: a chemical; copper sulphate. It is used to kill fungi,
etc.

=Bordeaux Mixture=: a mixture invented in Bordeaux, France, to destroy
disease-producing fungi.

=Bud= (noun): an undeveloped branch.

=Bud= (verb): to insert a bud from the scion upon the stock to insure
better fruit.

=Bud variation=: occasionally one bud on a plant will produce a branch
differing in some ways from the rest of the branches; this is bud
variation. The shoot that is produced by bud variation is called a
_sport_.

=Calyx=: the outermost row of leaves in a flower.

=Cambium=: the growing layer lying between the wood and the bark.

=Canon=: the shank bone above the fetlock in the fore and hind legs of a
horse.

=Carbohydrates=: carbohydrates are foods free from nitrogen. They make
up the largest part of all vegetables. Examples are sugar, starch, and
cellulose.

=Carbolic acid=: a chemical often used to kill or prevent the growth of
germs, bacteria, fungi, etc.

=Carbon=: a chemical element. Charcoal is nearly pure carbon.

=Carbon disulphide=: a chemical used to kill insects.

=Carbonic acid gas=: a gas consisting of carbon and oxygen. It is
produced by breathing, and whenever carbon is burned. It is the source
of the carbon in plants.

=Cereal=: the name given to grasses that are raised for the food
contained in their seeds, such as corn, wheat, rice.

=Cobalt=: a poisonous chemical used to kill insects.

=Cocoon=: the case made by an insect to contain its larva or pupa.

=Commercial fertilizer=: an enriching plant food bought to improve soil.

=Compact=: a soil