Ontario Teachers' Manuals: Nature Study

by Ontario. Department of Education

TWIGS AND BUDS

The study of buds is a part of tree study and may be taken as observation work in the class-room. This somewhat detailed study should follow the general lessons on tree study.

The materials for the lessons may be collected by the pupils at the time of the field lesson and kept fresh in a jar of water until required for use.

LESSON ON TWIGS

Materials.—A twig of horse-chestnut about six inches long, for each pupil.

A twig of the same tree with the leaves still on it.

Observations.—The twigs are distributed and the teacher asks the pupils to examine them and to describe all marks and projections that can be found on the twig.

Answers are required from the pupils separately. The pupil's answer in each case should be sufficiently clear for all the class to recognize the feature that the answer is intended to describe. A few brief questions will guide the answerer in making his description more definite, but the description should be the result of the pupil's observation and expressed in his own words.

The meaning or use of each feature should be discussed, when possible, immediately after it has been described.

The following features will be discovered and the problems suggested will be solved:

The brown or greenish-brown bark.

The buds.

One bud (sometimes two) is at the end of the twig.

Some buds are along the side of the twig.

What caused the end bud to grow larger than the others?

There is a leaf scar under each bud.

Of what use is it to the bud to be between the twig and the leaf stalk?

The bands of rings, one or more on each twig.

The tiny oval pores, each surrounded by a little raised band.

The detailed study of the buds is left for a separate lesson.

FURTHER STUDY OF TWIGS

The study in detail of various features is illustrated in the following:

Look closely at the leaf scars and describe them fully, as to shape, colour, and marks.

Do the scars look like fresh wounds, or are they healed over? Of what use to the tree is the healing of the scar?

We will learn later that the part of the twig between each pair of bands of rings represents one year's growth. How old is your twig? Who has the oldest twig?

Do all twigs grow at the same rate?

Who has the twig that had the most rapid growth?

To the teacher.—The bud at the end of the twig or its branches is called the end bud; there are two leaf scars underneath it. The buds along the sides of the stem are called side buds, the latter are smaller than the end bud. The bud situated between the stem of the leaf and the twig is in a sheltered position. This position also puts the bud close to the pantry door, for the plant food is prepared in the leaf. The leaf scars are yellowish-brown, or if they are the scars from the leaves of former years, are dark brown in colour. Each scar is shaped like a horse-shoe and tiny dots are found in the position that the horse-shoe nails would have. Even before the leaf falls, a layer of corklike substance has formed over the scar. This layer is a protection against the entrance of frost and rain and germs of fungi and it also prevents the loss of sap from the scar. The tiny oval pores, each as large as the point of a needle, are the breathing pores of the twig. The bands of rings are the scars of the scales of the end buds of successive years. This latter fact can be discovered when the bud is opening.

REVIEW LESSON

The review lesson should consist of a review of the points taken up in the lessons that were based on the horse-chestnut twig, supplemented by the examination of the twigs of elm, apple, or lilac.

LESSON ON BUDS

Materials.—Twigs and buds of horse-chestnut, one for each pupil. An opening bud. (A bud or a twig placed in water in a warm room will develop rapidly.)

Lesson.—Distribute specimens, and review the positions of the buds.

Pupils examine the buds and tell all they can about them. They describe the colour, shape, and size of the buds, and also their gummy and scalelike covering.

Of what use are the gum and scales? Of what use is the brown colour of the bud?

They next find out what is inside the little brown house. They open the buds and try to identify the contents. There will be some uncertainty as to the meaning of the contents. Leave this over till spring.

To the teacher.—The brown colour of the bud makes it an absorbent of sunlight, and also serves as a protection from observation by the sharp eyes of bud-eating birds. The gummy scales are waterproof, and the scales, by spreading open gradually, cause the waterproof property to be retained even after the bud has grown quite large. The inner part of the bud is composed of two, four, or six tiny leaves folded up and supported on a short bit of stem. Some of the buds have, in addition to leaves, a tiny young flower cluster. All of these things are densely covered with white down. The down is the fur coat to protect the tender parts from the cold.

REVIEW LESSON

Review the lesson on buds, but substitute buds of the lilac or apple for the horse-chestnut buds of the original lesson.

CORRELATIONS

The observational study of the buds and twigs is a good preparation for busy work in art and manual training, and the pupils may be assigned exercises, such as charcoal drawing of a horse-chestnut twig, paper cutting of a lilac twig and buds, clay or plasticine modelling of twigs and buds.

For oral and written language exercises, enlarge the vocabulary of the pupils by requiring sentences containing the words—scales, twigs, buds, protection, terminal, lateral, leaf stalk, blade, etc.