oduction and dispersal of its
seeds.

Ask the pupils to be on the alert to find examples of plants in which
provision is made for the dispersal of the seeds, and to bring these
plants to the class for the next lesson.

DETAILED STUDY OF SEED DISPERSAL

II. CLASS-ROOM LESSON

Make use of the specimens gathered by the pupils and by the teacher for
observing and classifying as follows:

1. Seeds that steal rides. Examples--burdock, blue burr, pitch-fork
weed, barley, stick-tight, hound's tongue.

2. Seeds that are carried in edible fruits which have attractive
colours, tastes, etc. Examples--apple, grape, cherry, rowan, hawthorn.

3. Seeds that are carried by the wind. Examples--dandelion, thistle,
milkweed, maple, pine, elm.

4. Seeds that are scattered by being shot from bursting pods.
Examples--violet, jewel-weed (touch-me-not), sweet-pea, witch-hazel.

5. Seeds that are scattered by plants which are rolled along by the
wind. Examples--Russian thistle, tumble-mustard, tumble-grass.

6. Seeds that float. Very many seeds float, although not specially
fitted for floating, and some, such as the cocoa-nut and water-lily, are
especially adapted for dispersal by water.

_To the teacher._--Require the pupils to observe the special structure
that facilitates the dispersal of the seed. As an illustration, ask the
pupils to find the seeds of the burdock and to describe what the burr is
really like. They find that the burr is a little basket filled with
seeds. The basket has many little hooks which catch on the hair of
animals and, since these hooks turn inwards, they serve to hold the
basket in such a position that all the seeds are not likely to drop out
at one time. The pupils should also observe that these baskets are quite
firmly attached to the parent plant until the seeds are ripe; after that
the baskets break off the plant at the slightest pull.

SEED COLLECTIONS

During late summer and in the autumn the seeds of the weeds that have
been identified by the pupils should be collected.

Instruct the pupils to rub the ripened seed pods between the hands until
the seeds are thrashed out, at the same time blowing away the chaff. The
seeds are now placed in small phials or in small envelopes and these are
carefully labelled. If possible, fill each phial so that there may be
sufficient seed for use by all the members of the class in the lessons
on seed description and identification which are to be taken during the