ble. pearance in the solar microscope. It is all composed of extremely diminutive netted bags, of thick juice, without any vessels-in short, it is the first formation of the pabulum or softer part of the wood; and when ready prepared for the sap vessels, they shoot their way through this soft substance. In a graft, which I have repeatedly tied up again, before the vessels had begun to appear, and when I reopened it, I found them and the wood perfectly complete. I have taken this matter from a graft, from a fresh budded How obtaina plant; from the interior of a seed, and sometimes from the shooting of the fresh line of the wood, but this is generally too hasty a performance to profit by; the fresh wound of a tree is the best way of getting it (next to a graft) if well preserved from the air, and in a fortnight plenty will be found. But the specimen must be quickly taken, or the wood vessels will shoot. This is the true cambium, the softer part of the wood, before the sap vessels shoot. But I must notice, that the bark is not made in the same manner it is formed all at once, soft and hard; the vessels shoot, while the rest is forming. Mr. Knight very properly observes, that in a graft the fresh wood always resembles exactly the wood of the graft, and not the stock, I am, Sir, Your obliged servant, AGNES IBBETSON. The five classes into which I have divided the seeds. Common seed, or first class. Oak, elm, beech, horse-chest Mammiferous, or teat-bear-out, &c.; rose, laurel, bud ing. See walnut, Pl. V, figs. 1, 2, 3; apricot, figs. 4, 5, 6. lea, &c.; burdock, sunflower, flowers. Second class. Leaf-bearing or foliferous. See figs. 8 and 9, showing the whole embryo, when forced out of the seed in the manner described above; and fig. 7, the heart, or corculum, alone, Firs and spontaneous plants Classes of seeds. Third class. Caniculated, or channelled, so called, from a channel, which begins within the recess, and runs on beyond the primordial leaf. See fig. 10, the upper part representing the corculum; the lower, the whole of the embryo together. A numerous class, containing most of the papilionaceous, cruciform, and labiate plants. Fourth class. Nonmammiferous, having no the primordial leaves as Grasses and palms. Fifth class. Compound or mixed seed. { Nymphea, coffee, some spices, and cotton tree. Fig. 6 is merely to show the manner in which the stalk, n, runs through the corculum; the primordial leaves, e e, being within; the cotyledons, cc, shooting from the out⚫ward cylinder. In all the figures the same letters of reference are used. a, the line of life, or impregnating duct. b, nourishing vessels. c, cotyledons. d, the breast and teats. e, primordial leaves. f, the recess. n, the stalk. |