Between the sycamore seed and the wall of its case is a layer of fine hair (h, Fig. 4), which forms a warm nest for the seed in winter. The seed is surrounded by a thin, brown seed-coat, and consists mainly of two cotyledons, but these are very different from any yet described. Each is a green leaf, measuring, when unfolded, about an inch in length. It is first folded across the middle of its length, and then rolled up into a close coil with its fellow. The coils are very plainly to be seen when the seed coat is removed, or when the whole seed is cut through, by a sharp knife, in the plane of the wing. Running down one side of the seed is a green rod, the radicle (R, Fig. 4). The two cotyledons (cot. 1 and cot. 2) spring from its upper end, and between them is the tiny plumule (pl.) The sycamore seed bears more resemblance to the mustard seed than to the others, but it is on a much larger scale. In each of these two seeds the cotyledons are plainly leaves, while in the others their nature is disguised by the great accumulation of stored food in them. 2. THE EARLY STAGES OF GROWTH OF SEEDS WITH TWO COTYLEDONS. If the seeds which were sown in damp sawdust and on flannel are kept warm they will soon be ready for study. You should remember that at present your object is not so much to rear the plants as to find out how they grow. As soon, therefore, as any sign of growth is to be seen when you take a seed out, you should begin to examine them at regular intervals, taking one or two out every day and leaving the rest to continue their development. Keep the sawdust damp, but not wet. 1. The pea and bean.—(a) General development.—Very soon [Pg 10] the seed-coat splits at the micropyle-end of the stalk-scar, and the end of the radicle protrudes. Does the radicle grow upwards or downwards? Observe that even if the seed was so planted that the micropyle was at the top, the radicle turns over and grows straight down. Turn over a seedling and see if you can persuade the radicle to grow upwards. Open a seed when the radicle is about an inch long, and see what the plumule is doing. It is still enclosed in the seed-coat, and lies between the cotyledons, but is larger than at first. As the growth proceeds the cotyledons begin to separate near the top of the radicle, and you can get a glimpse of the plumule.