That which without dissection shews it self, is the Coarcture: I cannot say of the Root, nor of the Trunk; but what I chuse here to mention, as standing betwixt them, and so being common to them both; all their Parts being here bound in closer together, as in the tops of the grown Roots of very many Plants, is apparent.
Of the Parts of the Trunk, the first occurring is its Skin: The Formation whereof, is not from the Air, but in the Seed, from whence it is originated; being the production of the Cuticle, there investing the two Lobes and Plume.
The next Part is the Cortical Body; which here in the Trunk is no new substantial formation; but, as is that of the Root, originated from the Parenchyma of the Seed; and is only the increase and augmentation thereof. The Skin, this Cortical Body properly so call’d, and (for the most part) some Fibers of the Lignous mixed herewith, all together make the Barque.
Next, the Lignous Body, which, whether it be visibly divided into many softer Fibres, as in Fennel, and most Plants; or that its parts stand more compact and close, shewing one hard, firm and solid piece, as in Trees; it is in all one and the same Body; and that not formed originally in the Trunk, but in the Seed; being nothing else but the prolongation of the Inner Body distributed in the Lobes and Plume thereof.
Lastly, The Insertions and Pith are here originated likewise from the Plume, as the same in the Root from the Radicle: So that as to their substantial Parts, the Lobes of the Seed, the Radicle and Plume, the Root and Trunk are all one.
Yet some things are more fairly observable in the Trunk. First, the Latitudinal shootings of the Lignous Body, which in Trunks of several years growth, are visible in so many Rings, as is commonly known: For several young Fibres of the Lignous Body, as in the Root, so here, shooting into the Cortical one year, and the spaces betwixt them being after fill’d up with more (I think not till) the next, at length they become altogether a firm compact Ring; the perfection of one Ring, and the ground-work of another being thus made concomitantly.
From these Annual younger Fibres it is, that although the Cortical Body and Pith are both of the same substantial nature, and their Pores little different; yet whereas the Pith, which the first year is green, and of all the Parts the fullest of Sap, becomes afterwards white and dry; the Cortical Body, on the contrary, so long as the Tree grows, ever keepeth green and moist, sc. because the said Fibers annually shoot into, and so communicate with it.
The Pores likewise of the Lignous Body, many of them in well-grown Timber, as in Oaken boards, are very conspicuous, in cutting both lengthwise and traverse; they very seldom run one into another, but keep, like so many several Vessels, all along distinct; as by cutting, and so following any one of them as far as you please, for a Foot or half a Yard, or more together, may be observ’d.
These greater Pores, though in Wainscot, Tables, and the like, where they have lain long open, they are but meer Vacuities, and so would be thought to contain only Sap in the Tree, and afterwards only Air; yet upon a fresh cut, each of them may be seen fill’d up with a light and spongie Body, which by Glasses, and even by the bare eye, appears to be a perfect Pith; sometimes entire, and sometimes more or less broken.
Besides these, there are a lesser sort; which, by the help of a Microscope, also appear, if not to be fill’d up with a Pith, yet to contain certain light and filmy parts, more or fewer, of a Pithy nature within them.