And now the arum begins its great preparations for the act of flowering. Everybody knows the general shape of the arum blossom--if not in our own purple cuckoo-pint, at least in the big white 'Æthiopian lilies' which form such frequent ornaments of cottage windows. Clearly, this is a flower which the plant cannot produce without laying up a good stock of material beforehand. So it sets to work accumulating starch in its root. This starch it manufactures in its leaves, and then buries deep underground in a tuber, by means of the sap, so as to secure it from the attacks of rodents, who too frequently appropriate to themselves the food intended by plants for other purposes. If you examine the tuber before the arum has blossomed, you will find it large and solid; but if you dig it up in the autumn after the seeds have ripened, you will see that it is flaccid and drained; all its starches and other contents have gone to make up the flower, the fruit, and the stalk which bore them. But the tuber has a further protection against enemies besides its deep underground position. It contains an acrid juice like that of the leaves, which sufficiently guards it against four-footed depredators. Man, however, that most persistent of persecutors, has found out a way to separate the juice from the starch; and in St. Helena the big white arum is cultivated as a food-plant, and yields the meal in common use among the inhabitants. When the arum has laid by enough starch to make a flower it begins to send up a tall stalk, on the top of which grows the curious hooded blossom known to be one of the earliest forms still surviving upon earth. But now its object is to attract, not to repel, the animal world; for it is an insect-fertilised flower, and it requires the aid of small flies to carry the pollen from blossom to blossom. For this purpose it has a purple sheath around its head of flowers and a tall spike on which they are arranged in two clusters, the male blossoms above and the female below. This spike is bright yellow in the cultivated species. The fertilisation is one of the most interesting episodes in all nature, but it would take too long to describe here in full. The flies go from one arum to another, attracted by the colour, in search of pollen; and the pistils, or female flowers, ripen first. Then the pollen falls from the stamens or male flowers on the bodies of the flies, and dusts them all over with yellow powder. The insects, when once they have entered, are imprisoned until the pollen is ready to drop, by means of several little hairs, pointing downwards, and preventing their exit on the principle of an eel-trap or lobster-pot. But as soon as the pollen is discharged the hairs wither away, and then the flies are free to visit a second arum. Here they carry the fertilising dust with which they are covered to the ripe pistils, and so enable them to set their seed; but, instead of getting away again as