The bulbs of plants are another kind of winter-cradle, or hybernacle, adhering to the descending trunk, and are found in the perennial herbaceous plants which are too tender to bear the cold of the winter. The production of these subterraneous winter lodges, is not yet perhaps clearly understood, they have been distributed by Linneus according to their forms into scaly, solid, coated, and jointed bulbs, which however does not elucidate their manner of production. As the buds of trees may be truly esteemed individual annual plants, their roots constituting the bark of the tree, it follows that these roots (viz. of each individual bud) spread themselves over the last years bark, making a new bark over the old one, and thence descending cover with a new bark the old roots also in the same manner. A similar circumstance I suppose to happen in some herbaceous plants, that is, a new bark is annually produced over the old root, and thus for some years at least the old root or caudex increases in size and puts up new stems. As these roots increase in size the central part I suppose changes like the internal wood of a tree and does not possess any vegetable life, and therefore gives out no fibres or rootlets, and hence appears bitten off, as in valerian, plantain, and devil's-bit. And this decay of the central part of the root I suppose has given occasion to the belief of the root-fibres drawing down the bulb so much insisted on by Mr. Milne in his Botanical Dictionary, Art. Bulb. From the observations and drawings of various kinds of bulbous roots at different times of their growth, sent me by a young lady of nice observation, it appears probable that all bulbous roots properly so called perish annually in this climate: Bradley, Miller, and the Author of Spectacle de la Nature, observe that the tulip annually renews its bulb, for the stalk of the old flower is found under the old dry coat but on the outside of the new bulb. This large new bulb is the flowering bulb, but besides this there are other small new bulbs produced between the coats of this large one but from the same caudex, (or circle from which the root-fibres spring;) these small bulbs are leaf-bearing bulbs, and renew themselves annually with increasing size till they bear flowers.