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 winter months, when Nature Study material is less plentiful than it is in the summer and autumn. The phials or envelopes may be stored in a shallow box, or the phials may be mounted on a stout card. They may be attached to this card either by stout thread sewed through the card and passing around the phial, or by brass cleats, which may be obtained with the phials from dealers in Nature Study supplies.