Ontario Teachers' Manuals: Nature Study Part 27

ANNUALS

~Observations.~--Some plants, such as poppy and candy-tuft, are early blooming, while others, such as aster and cosmos, bloom in late summer, hence a selection should be made that will yield a succession of bloom throughout the season.

Some are hardy annuals which can be grown from open planting, even when the weather is cold. These often seed themselves; for example, sweet-pea, morning-glory, phlox, poppy, sweet-alyssum.

Some are half-hardy annuals, such as asters, balsams, stocks, and nasturtiums. These must be started indoors or in hotbeds, or if in plots, not until the soil is quite warm.

The heights of annuals vary, and consequently they must be arranged in the bed in such a way that tall plants will not shade the short ones.

BIENNIALS

~Observations.~--During the first year food is stored in the root of the turnip, carrot, parsnip, and beet, in the leaves of the cabbage, and in the stem of the hollyhock.

Flowers and seeds are produced during the second year, and the storehouse becomes empty, dry, and woody. Preparation for winter is therefore, in the case of biennials, preparation for a renewal of growth the following spring.

PERENNIALS

~Observations.~--The highest forms of plant life are found in this cla.s.s; namely, the strong, large, hardy trees and shrubs.

The herbaceous perennials are equipped with underground parts that act as storehouses of food to ensure the growth of the plant through successive seasons. Examples: the roots of dahlia, rhubarb, dandelion, and chicory; the underground stems of potato, onion, tulip, scutch-gra.s.s, Canada thistle, etc.

Many of the wild flowers that bloom in early spring belong to this cla.s.s, and their rapid growth then is made possible by the store of food in the underground parts. Examples: trillium, bloodroot, squirrel-corn, Indian turnip, Solomon's seal, etc.

SPECIAL STUDY OF GARDEN PLANTS

A few plants should be selected for special study, and the following are recommended: annuals--sweet-pea, pumpkin, and corn; biennials--cabbage, parsnip, and carrot; perennials--dahlia, rhubarb, and couch-gra.s.s.

It is desirable that the observations be made upon the plants in the garden, but they may be conducted in the cla.s.s-room upon specimens brought into the room by the pupils.

SWEET-PEA

Examine the stem of the sweet-pea and describe its form, its uniform slender structure, and the fact that it climbs. Find out just how it climbs. The pupils will observe the tendrils, which are extensions of the midribs of the leaves.

Describe the leaves, noting what is meant by calling them _compound_.

Observe the position of the flower, its colours, odour, size, and form.

What insect does it resemble in shape? What different features of the flower enable it to attract attention?

The names and uses of the floral organs may be taught to this cla.s.s. For example:

Pupils find the green blanket that protects the bud. This is the _calyx_.

The beautiful, attractive part is the _corolla_.

The parts that produce the pollen are called _stamens_.

The case that holds the seeds is the _pistil_.

Examine flowers of different ages and trace the change from the minute pistil to the pod.

Study, comparatively, the flowers of the field-pea, bean, or wild vetch.

Select a few of the finest blossoms of the sweet-pea and put tags on them while they are still in bloom. When they ripen, collect the seeds and preserve them for spring planting.

Conduct observation lessons on the pumpkin and corn, in which the pupils will discover such facts as those given below.

PUMPKIN

Notice the method of growth--the stem no stronger than that of the sweet-pea, but lying flat on the ground. Notice the little roots sent out here and there where the stem touches the ground. This gives extra nourishment. The leaves are not numerous and grow only in one direction, but are very large--entirely too large to be borne upon an upright stem.

Notice the large funnel-like flowers and that not all of them set fruit.

Examine the flowers. Some of them have stamens for producing pollen, but no pistil. These never produce fruit, for pumpkins are simply enlarged and ripened pistils. Look for insects and examine them to find out whether they are carrying pollen. Notice younger pumpkins and even blossoms toward the end of the vine. Pick all the blossoms and small pumpkins off a vine, leaving only one of the best growing pumpkins. See whether this one grows larger than one of equal age on a vine having young pumpkins developing on it. Notice the arrangement of the seeds inside a ripe pumpkin. Collect some seeds, wash clean, and dry for spring planting. It is desirable to plant pumpkins late in May, so that they will have flowers on their vines as late as September.

Study the flowers of the cuc.u.mber and compare them with those of the pumpkin.

CORN

This plant is native to America, was greatly prized by the aborigines, and even worshipped by some of them. Note the upright character of the plant and how the stalk is divided into sections by the joints, or nodes. Count these joints and also the leaves, and note the relationship of leaves and joints in the stalk, and how the leaves come off in different directions so as not to shade each other. Note the strong, stringy threads in the leaf, which give strength to the leaf as well as circulation of sap. They are strong and elastic, allowing of movement.

The same strengthening fibres are seen in the stalk when it is broken across. In the stalk these fibres are arranged in a tubular form, as this gives greatest strength, the centre being soft and weak. The stalks are largest near the base, where the greatest stiffness is required. The nodes are also closer together here for strength. The stem is made much stronger by the bases of the leaves being wrapped so firmly around for a distance above the point of attachment at the node. Notice the close-fitting sheath or rain-guard, where the blade of the leaf leaves the stalk. This prevents rain soaking down inside the leaf sheath, but lets it run down the outside to the root where it is needed. As the plant gets older and taller, new roots come out from the node next above the root and sometimes from the second node above. These prop-roots are needed for support as the stalk lengthens, and they also reinforce the feeding capacity.

Note the appearance of little cobs in the axils of the leaves. As soon as the silk appears, take a cob off and open it carefully. The little cob, which corresponds to the pistil in other plants, is covered with small and undeveloped kernels, and to each kernel one of the strands of so-called silk is attached. Whilst this little cob is forming, a bunch, or ta.s.sel, of flowers is forming on the top of the corn plant. Open one of these flowers and find the stamens with pollen-grains inside. This pollen, when shed, falls upon the silk, and each grain sends a tiny tube down inside the silk to the delicate ovules on the cob, fertilizing them and starting them to develop. The silk then withers. The wind carries this pollen.

Find out how the silk is fitted for catching the pollen. What is the need for the great quant.i.ty of pollen that the plant produces?

Strip off the husks and compare the tough, hard husks that are found on the outside with the soft paper-like husks found close to the cob. Show how each kind is fitted for its particular work.

Pupils make experiments in the corn plot to find:

1. Whether the corn grows faster:

(1) When the soil is kept mellow or when the soil is hard;

(2) When the days are warm or when they are cool;

(3) When the nights are cool or when they are warm.

2. The effect of growing black corn and golden corn in the same or in adjoining plots. Account for the result.

CORRELATIONS

Art: Clay-modelling and drawing exercises on the whole plant, and also upon the ear.

Literature: Interpretation and reading of "Blessing the Corn-fields", from _Hiawatha_.

History: The name Indian corn originated in the early colonial days of the Eastern and Central States, when the pioneers obtained corn from the Indians. The Indians showed the settlers how to kill the trees by girdling and how to plant the corn among the standing trunks, and thus have corn ready for roasting by August, and for grinding into meal or for boiling to make hominy by September.

SEED DISPERSAL

The lessons on seed dispersal which were begun in Form I should be continued in this Form.