Notes of Lessons: Biology, Class III

[We have thought that it might be of use to our readers (in their own families) to publish from month to month during the current year, Notes of Lessons prepared by students of the House of Education for the pupils of the Practising School. We should like to say, however, that such a Lesson is never given as a tour de force, but is always an illustration or an expansion of some part of the children’s regular studies (in the Parents’ Review School), some passage in one or other of their school books.—Ed.]

Subject: Botany • Group: Science • Class III • Time: 35 minutes

By Patty C. Nevitt-Bennett
The Parents’ Review, 1909, pp. 550-551

Objects

I. To interest the girls in Botany, by encouraging them to investigate for themselves.

II. To introduce the girls to a new Natural Order—Cruciferæ

III. To help them to compare and contrast the plants belonging to the Natural Order Cruciferæ, with those belonging to Ranunculaceæ which Order they studied last term.

Lesson

Step I.—Give each girl a specimen, i.e., a Wallflower. The name of this plant is bestowed upon it because it most frequently grows, in its wild state, upon old walls. Sometimes it is called “Gilliflower,” and in the old authors one finds mention of “Gilofre,” “Jereflouris,” and “Gariofilus,” and all these names are corrupt forms of the Latin Caryophyllum, which was given to the plant from its clove-like odour.

Step II.—Draw from the girls the description of the specimen in the following order:—Stem, Leaf, Inflorescence, Flower, Calyx, Corolla, Andræcuim, Pistil.

Step III.—Explain the reason of the saccate calyx. At the base of each of the two outer stamens there is a nectary. The filaments have to bend outwards to make room for this, and this causes the bulging out of the two inner sepals.

Step IV.—Draw the girls’ attention to the stamens. Explain how that when the anthers are young the part which opens faces the Pistil, but as they become mature they twist round so that really they seem to dehisce extrorsely. Ask the girls the reason for this twist of the stamens.

Step V.—Notice the characteristic Pistil: its bifid stigma, short style, and long flat Ovary which is spuriously bilocular owing to the development of a false dissepiment. It is on to the frame, “the replum” of this dissepiment that the ovules are attached.

Step VI.—Assign the specimen to its Natural Order,Cruciferæ, from Latin “crux” owing to the “cross-shape” of the flower, and also to its Division Dicotyledons.

Step VII.—Give the girls specimens of White Rock, Hedge Garlic and Honesty. From these and the Wallflower which they have just examined, let them find out the characteristic features of plants belonging to the Natural Order Cruciferæ.

Step VIII.—Draw from the girls the points of resemblance and contrast between plants belonging to the Order Cruciferæ and Ranunculaceæ, such as Points of resemblance, free calyx, free corolla, free hypogynous stamens, and superior pistil.

Also both Orders belong to the Division Dicotyledons.

Points of difference.

Ranunculaceæ.	Cruciferæ.
Stamens of equal length	Tetradynamous stamens, four long and two short
Fruit an etærio of achenesor follicles	Fruit a siliqua or silicula
Many plants poisonous	No plants poisonous