_Of the Trunk._
Having thus declar’d the degrees of _Vegetation_ in the _Root_; the
continuance hereof in the _Trunk_ shall next be shew’d: in order to
which, the Parts whereof this likewise is compounded, we shall first
observe.
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.
And these are all the Pores the best Glasses, which, (when upon these
Enquiries) we had at hand, would shew us. But the Learned and most
Ingenious Naturalist Mr. _Hook_ sheweth us moreover, besides these, a
third, and yet smaller sort; the description whereof I find he hath
given us amongst his _Microscopical Observations_. Of these Pores (as a
confirmation of what, in the Second Chapter, I have said of the Pores
of the _Lignous Body_ in general) he also demonstrates; that they are
all continuous and prolonged by the length of the _Trunk_; as are the
greater ones; the Experiment whereof he imparteth to be, by filling up,
suppose in a piece of _Char-coal_, all the said Pores with _Mercury_;
which appears to pass quite through them, in that by a very good Glass it
is visible in their Orifices at both ends; and without a Glass, by the
weight of the Coal alone, is also manifest.
Upon farther Enquiry, I likewise find, that the Pores of the _Lignous
Body_ in the _Trunk_ of Plants, which at first only supposed, by the help
of good Glasses are very fairly visible; each Fibre being perforated by
30, 50, 100, or hundreds of Pores. Or what I think is the truest notion
of them, that each Fibre, though it seem to the bare eye to be but one,
yet is indeed a great number of Fibres together; every Pore being not
meerly a space betwixt the several pores of the Wood, but the Concave
of a Fiber: So that if it be asked, what all that part of a Vegetable,
either Plant or Tree, which is properly call’d the woody part; what all
that is, I suppose, that is nothing else but a Cluster of innumerable and
most extraordinary small Vessels or concave Fibres. See _Fig. 15_.
Next the Insertions of the _Cortical Body_, which in the _Trunk_ of
a Tree saw’d athwart, are plainly discerned as they run from the
Circumference toward the Center; the whole Body of the Tree being visibly
compounded of two distinct Substances, that of the several Rings, and
that of the Insertions, running cross; shewing that in some resemblance
in a Plain, which the Lines of Latitude and of the Meridian do in a
Globe. See _Fig. 16_.
These Insertions are likewise very conspicuous in Sawing of Trees
length-wayes into Boards, and those plain’d, and wrought into Leaves for
Tables, Wainscot, Trenchers, and the like. In all which, as in course
Trenchers made of _Beech_, and Tables of Oak, there are many parts which
have a greater smoothness than the rest; and are so many inserted pieces
of the _Cortical Body_; which by reason of those of the _Lignous_, seem
to be discontinuous; although in the _Trunk_ they are extended throughout
its Breadth.
These Insertions, although as is said, of a quite distinct substance
from the _Lignous Body_, and so no where truly incorporated with it, yet
being they are in all parts, the one as the Warp, the other as the Woof,
mutually braced and inter-woven together, they thus constitute one strong
and firmly coherent Body.
As the Pores are greater or less, so are the Insertions also: To the bare
eye usually the greater only are discernable: But through an indifferent
_Microscope_ there are others also, much more both numerous and small,
distinctly apparent. So that, I think, we may observe, that as the grand
_Pith_ of the _Trunk_ communicates with, and is augmented by the greater
Insertions; so is the _Pith_ of each greater Pore originated from the
less; and those (at least) pithy parts in the Midling Pores, from others
still less; and suppose, that the least of all are so far intruded into
the smallest Pores, as only just to cause a kind of roughness on their
concave sides, and no more; to what end shall be said. See _Fig. 17_.
In none of all these Pores can we observe any thing which may have the
true nature and use of Valves, which is easily to admit that, to which
they will by no means allow a regress. And their non-existence is enough
evident, from what in the first Chapter we have said of the _Lobes_ of
the _Seed_: in whose _Seminal Root_, were there any _Valves_, it could
not be, that by a contrary course of the _Sap_, they should ever grow;
which yet, where-ever they turn into Dissimilar Leaves, they do. Or if
we consider the growth of the _Root_, which oftentimes is upward and
downward both at once.
The Insertions here in the _Trunk_ give us likewise a sight of the
position of their Pores. For in a plained piece of Oak, as in Wainscot,
Tables, _&c._ besides the larger Pores of the _Lignous Body_, which
run by the length of the _Trunk_; the Tract likewise of those of the
Insertions may be observed to be made by the breadth, and so directly
cross. Nor are they continuous as those of the _Lignous Body_, but very
short, as those both of the _Cortical Body_ and _Pith_, with which the
Insertions, as to their substance are congenerous. Yet they all stand so
together, as to be plainly ranked in even Lines or Rows throughout the
breadth of the _Trunk_: As the Tract of these Pores appear to the naked
Eye, see in _Fig. 18_. By the best Microscope I have at hand, I can only
observe the Ranks of the Pores; not the Pores themselves, saving here and
there one; wherefore I have not describ’d them.
The Pores of the _Pith_ likewise being larger here in the _Trunk_, are
better observable than in the _Root_: the width whereof, in comparison
with their sides so exquisitely thin, may by an Honey-Comb be grosly
exemplified; and is that also which the vast disproportion betwixt the
Bulk and weight of a dry _Pith_ doth enough declare. In the _Trunks_ of
some Plants, they are so ample and transparent, that in cutting both by
the length and breadth of the _Pith_, some of them, even to the bare eye
would seem to be considerably extended by the length of the said _Pith_;
which once I also thought they were, and that only the rest of them were
but short and discontinuous, and as ’tis said, somewhat answerable to
the Cells of an Honey-Comb. This was the nearest we could come to them,
by conjecture, and the assistance of the best Glasses we then had by us,
when upon enquiry into the nature of the _Pith:_ But that Worthy Person
newly mentioned Mr. _Hooke_ sheweth us, that the Pores of the _Pith_,
particularly of _Elder-Pith_, so far as they are visible, are all alike
discontinuous; and that the _Pith_ is nothing else (to use his own words)
but an heap of Bubbles.
Besides what this Observation informs us of here, it farther confirms
what in the second Chapter we have said of the Original of the _Pith_
and _Cortical Body_, and of the sameness of both their natures with the
_Parenchyma_ of the Seed. For, upon farther enquiry with better Glasses,
I find, that the _Parenchyma_ of the _Plume_ and _Radicle_, and even of
the _Lobes_ themselves, though not so apparently, is nothing else but a
Mass of Bubbles.
In the _Piths_ of many Plants, the greater Pores have some of them lesser
ones within them, and some of them are divided with cross Membranes: And
betwixt their several sides, have, I think, other smaller Pores visibly
interjected. However, that they are all permeable, is most certain. They
stand together not indeterminately, but in even Ranks or Trains; as those
of the Insertions by the breadth, so these by the length of the _Trunk_.
And thus far there is a general corresponding betwixt the part of the
_Root_ and _Trunk_: Yet are there some considerable Disparities betwixt
them; wherein, and how they come to pass, and to what especial use and
end, shall next be said.
We say then, that the _Sap_ being in the _Root_ by Filtrations,
Fermentations (and in what _Roots_ needful, perhaps by Circulation also)
duly prepar’d; the prime part thereof passing through the intermediate
Coarcture, in due moderation and purity is entertain’d at last into the
_Trunk_. And the _Sap_ of the _Trunk_ being purer and more volatile, and
so it self apt to ascend; the motion of the _Trunk_ likewise will be
more noble, receiving a disposition and tendency to ascend therewith.
And what by the _Sap_ the _Trunk_ is in part dispos’d to, by the
respective position and quantity of its Parts it is effectually enabled.
For whereas in the _Root_ the _Lignous Body_ being in proportion with
the _Cortical_, but little, and all lying close within its Center; it
must therefore needs be under its controul: on the contrary, being here
comparatively of greater quantity, and also more dilated, and having
divers of its Branches standing more abroad towards the Circumference, as
both in the Leaves and Body of the young _Trunk_ and _Plume_, is seen;
it will in its own tendency to ascend, reduce the _Cortical Body_ to a
compliance with it.
And the _Trunk_ thus standing from under the restraint of the Mould in
the open Air, the disposition of its Parts originally different from
that of the Parts in the Root will not only be continued, but improved:
For by the force and pressure of the _Sap_ in its collateral Motion,
the _Lignous Body_ will now more freely and farther be dilated. And
this being dilated, the _Cortical Body_ also, must needs be inserted;
and is therefore in proportion alwayes more or less smaller here in the
_Trunk_, than in the _Root_. And as the _Cortical Body_ lessens, so the
_Pith_ will be enlarged, and by the same proportion is here greater. And
the _Pith_ being enlarged it self, its Pores (the _Lignous Body_, upon
its dilatation, as it were tentering and stretching out all their sides)
must needs likewise be enlarged with it, and accordingly are ever greater
in the _Pith_ of the _Trunk_, than of the _Root_. And the dilatation of
the _Lignous Body_ still continued, it follows, that whereas the _Pith_
descendent in the _Root_, is not only in proportion less and less, but
also in the smaller extremities thereof, and sometimes higher altogether
absent: Contrariwise, in the _Trunk_ it is not only continued to its
top, but also there in proportion equally ample with what it is in any
other inferiour part.
But although the openness of the Ayr permitting be alwayes alike; yet the
Energy of the _Sap_ effecting; being different; as therefore that doth,
the dilatation of the _Trunk_ will also vary. If that be less, so is
this; as in the _Trunks_ of most Trees: If that be greater, so is this;
as in Plants is common; the _Lignous Body_ being usually so far dilated,
that the _utmost shootings_ thereof may easily be seen to jut out, and
adjoyn to the Skin. And if the _Sap_ be still of greater energy, it so
far dilates the _Lignous Body_, as not only to amplifie the _Pith_ and
all its Pores; but also so far to stretch them out, as to make them tear.
Whereupon either running again into the _Cortical Body_, or shrinking up
towards it, the _Trunk_ thus sometimes becomes an _hollow Stalk_, the
_Pith_ being wholly, or in part voyded. But generally it keeps entire;
and where it doth, the same proportion and respect to the _Lignous_ and
_Cortical Bodies_, as is said. The Consequences of all which will be,
the strength of the _Trunk_, the security and plenty of the _Sap_, its
Fermentation will be quicker, its Distribution more effectual, and its
Advancement more sufficient.
First, the erect growth and strength of the _Trunk_; this being by the
position of its several parts effected: For besides the slendering of
the _Trunk_ still towards the top, the Circumferential position of the
_Lignous Body_ likewise is, and that eminently hereunto subservient: So
that as the _Lignous Body_ in the smaller part of the _Root_ standing
Central, we may thence conceive and see their pliableness to any
oblique motion; so here, on the contrary, the _Lignous Body_ standing
wide, it thus becomes the strength of the _Trunk_, and most advantageous
to its perpendicular growth. We see the same Design in _Bones_ and
_Feathers_: The strongest _Bones_, as those in the Legs, are hollow.
Now should we suppose the same _Bone_ to be contracted into a Solid
Body, although now it would be no heavier, and in that respect, as apt
for motion; yet would it have far less strength, than as it is dilated
to a Circumferential posture. And so for _Quills_, which, for the same
Reasons, in subserviency to flight, we see how exceeding light they are,
and yet, in comparison with the thinness of their Body, how very strong:
We see it not only in Nature, but Art. For hence it is that _Joyners_
and _Carpenters_ unite and set together their Timber-pieces and several
Works oftentimes with double Joynts; which, although they are no thicker
than a single one might be made, yet standing at a distance, have a
greater strength than that could have. And the same Architecture will
have the same use in the _Trunks_ of Plants, in most whereof ’tis very
apparent; as for instance, in Corn: For Nature designing its _Sap_ a
great Ascent for its higher maturity, hath given it a tall _Trunk_; but
to prevent its ravenous despoiling either of the Ear or Soyl; although it
be tall, yet are its sides but thin: and because again, it should grow
not only tall and thriftily, but for avoiding propping up, strongly too;
therefore, as its height is over-proportioned to the thinness of its
sides, so is its Circumference also; being so far dilated as to parallel
a _Quill_ it self. Besides the position of the _Lignous Body_ within the
compass of a Ring, we see some shootings thereof often standing beyond
the Circumference of the said Ring, making sometimes a triangular, oftner
a quadrangular Body of the _Trunk_; to the end, that the Ring being but
thin, and not self-sufficient, these, like Splinters to _Bones_, might
add strength and stability to it.
Next, the security and plenty of the _Sap_. For should the _Lignous
Body_, as it doth in the _Root_, its smaller parts, stand Central here
also, and so the _Cortical_ wholly surround it: the greater part of the
_Sap_ would thus be more immediately expos’d to the Sun and ayr; and
being lodg’d in a laxe Body, by them continually be prey’d upon, and
as fast as supplied to the _Trunk_, be exhausted. Whereas the _Pith_
standing in the Center, the _Sap_ therein being not only most remote
from the Ayr and Sun, but by the _Barque_, and especially the _Wood_,
being also surrounded and doubly immur’d, will very securely and
copiously be conveyed to all the Collateral parts, and (as shall be said
how) the top of the _Trunk_.
And the _Sap_ by the amplitude, and great porosity of the _Pith_ being
herein more copious, its Fermentation also will be quicker; which we see
in all Liquors by standing in a greater quantity together, proceeds more
kindly: And being tunn’d up within the _Wood_, is at the same time not
only secur’d from loss, but all extream mutations, the Day being thus not
too hot, nor the Night too cold for it.
And the Fermentation hereof being quicker, its motion also will be
stronger, and its distribution more effectual, not only to the
dilatation of the _Trunk_, but likewise the shooting out of the Branches.
Whence it is, that in the Bodies of Trees, the _Barque_ of it self,
though it be sappy, and many Fibres of the _Lignous Body_ mixed with it,
yet seldom sendeth forth any; and that in Plants, those with the least
_Pith_ (other advantages not supplying this defect) have the fewest or
smallest Branches, or other collateral Growths: and that _Corn_, which
hath no _Pith_, hath neither any Branches.
Lastly, the Advancement of the _Sap_ will hence also be more ready and
sufficient. For the understanding where, and how, we suppose that in all
_Trunks_ whatsoever there are two parts joyntly hereunto subservient.
In some the _Lignous Body_ and the _Cortical_, as in older _Trunks_,
the _Pith_ being either excluded or dried: But in most, principally
the _Lignous Body_ and _Pith_; as in most Annual Growths of Trees; but
especially Plants, where the _Cortical Body_ is usually much and often
wholly inserted.
Of the _Lignous_ body it is so apparent by its Pores, or rather by its
Vessels, that we need no farther evidence. For to what end are Vessels
but for the conveyance of Liquor? And is that also, which upon cutting
the young Branch of a Sappy Tree or Plant, by an accurate and steady view
may be observed. But when I say the Pores of the _Lignous Body_, I mean
principally them of the younger shootings, both those which make the new
Ring, and those which are mixed with the _Cortical Body_ in the _Barque_:
that which ascendeth by the Pores of the older Wood, being probably,
because in less quantity, more in form of a Vapour, than a Liquor. Yet
that which drenching into the sides of its Pores, is with all thereunto
sufficient Aliment; as we see _Orpine_, _Onions_, &c. only standing in
a moyster Ayr will often grow; And being likewise in part supplied by
the Insertions from the younger Shoots: But especially, because as it
is but little, so it serveth only for the growth of the said _Older
Wood_, and no more; whereas the more copious Aliment ascendent by the
younger Shoots, subserves not only their own growth, but the generation
of others; and is besides with that in the _Cortical Body_ the Fountain
of _Perspirations_, which we know even in Animals are much more abundant
than the _Nutritive parts_; and doubtless in a _Vegetable_ are still much
more.
But these Pores, although they are a free and open way to the ascending
_Sap_; yet that meer Pores or Vessels should be able of themselves
to advance the _Sap_ with that speed, strength & plenty, and to that
height, as is necessary, cannot probably be supposed. It follows then,
that herein we must grant the _Pith_ a joynt service. And why else in
the smaller parts of the _Root_, where the _Pith_ is often wanting, are
the Pores there greater? Why is the _Pith_ in all primitive growths the
most _Sappy_ part, why hath it so great a stock of _Sap_, if not after
due maturation within it self still to be disbursed into the Fibres of
the _Lignous Body_? Why are the annual growths of all both Plants and
Trees with great Piths, the quickest and the longest? But how are the
Pores of the _Pith_ permeable? That they are so, both from their being
capable of a repletion with _Sap_, and of being again wholly emptied of
it, and again, instead thereof fill’d with Ayr, is as certain as that
they are Pores. That they are permeable, by the breadth, appears from the
dilatation of the _Lignous Body_, and from the production of Branches,
as hath been, and shall hereafter be said. And how else is there a
Communion betwixt this and the _Cortical Body_? That they are so also,
by the length, is probable, because by the best _Microscope_ we cannot
yet observ, that they are visibly more open by the breadth, than by the
length. And withal are ranked by the length, as those of the Insertions
by the breadth of the _Trunk_. But if you set a piece of dry _Elder-Pith_
in some tinged Liquor, why then doth it not penetrate the Pores, so as
to ascend through the Body of the _Pith_? The plain reason is, because
they are all fill’d with Ayr. Whereas the _Pith_ in a Vegetating Plant,
as its Parts or Pores are still generated, they are at the same time
also fill’d with _Sap_; which, as ’tis gradually spent, is still repair’d
by more succeeding, and so the Ayr still kept out; as in all primitive
growths, and the _Pith_ of _Elder_ it self: Yet the same _Pith_, by
reason of the following Winter, wanting a more copious and quick supply
of _Sap_, thus once become, ever after keeps dry. And since in the
aforesaid Trial the Liquor only ascends by the sides of the _Pith_, that
is of its broken Pores, we should thence by the same reason conclude that
they are not penetrable by the breadth neither, and so no way; and then
it need not be ask’d what would follow. But certainly the _Sap_ in the
Pores of the _Pith_ is discharged and repaired every moment, as by its
shriv’ling up; upon cutting the Plant is evident.
We suppose then, that as the _Sap_ ascendeth into the _Trunk_ by the
_Lignous Body_, so partly also by the _Pith_. For a piece of _Cotton_
with one end immers’d in some tinged Liquor, and with the other erect
above, though it will not imbibe the Liquor so far as to over-run at
the top, yet so as to advance towards it, it will; so here, the _Pith_
being a porous and spongy Body, and in its Vegetating state its Pores
also permeable, as a curious Filtre of Natures own contrivance, it thus
advanceth, or as people use to say, sucks up the _Sap_. Yet as it is seen
of the Liquor in the Cotton; so likewise are we to suppose it of the
_Sap_ in the _Pith_; that though it riseth up for some way, yet is their
some term, beyond which it riseth not, and towards which the motion of
the ascending _Sap_ is more and more broken, weak and slow, and so the
quantity thereof less and less. But because the _Sap_ moveth not only
by the length, but breadth of the _Pith_; at the same time therefore
as it partly ascendeth by the _Pith_, it is likewise in part pressed
into the _Lignous Body_ or into its Pores. And since the motion of the
_Sap_ by the breadth of the _Pith_ not being far continued, and but
collateral, is more prone and easie than the perpendicular, or by its
length; it therefore follows, that the collateral motion of the _Sap_,
at such a height or part of the _Pith_, will be equally strong with the
perpendicular at another part, though somewhat beneath it; and that
where the perpendicular is more broken and weak, the collateral will be
less; and consequently where the perpendicular tendency of the _Sap_
hath its term, the collateral tendency thereof, and so its pressure into
the Pores of the _Lignous Body_ will still continue. Through which, in
that they are small, and so their sides almost contiguous, the _Sap_
as fast as pressed into them will easily run up; as betwixt the two
halves of a Stick first slit, and then tied somewhat loosely together,
may also any Liquor be observed to do. And the sides of the said Pores
being not smooth, but by the intrusion of the smallest insertions made
somewhat rough; by that means the higher and more facile ascent of the
_Sap_ therein will farther be promoted. By all which Advantages the
facility and strength of that ascent will be continued higher in the said
Pores than in the _Pith_. Yet since this also, as well as that in the
_Pith_ will have its term; the _Sap_, although got thus far, would yet
at last be stagnant, or at least its ascent be very sparing, slow and
feeble, if not some way or other re-inforced. Wherefore, as the _Sap_
moving by the breadth of the _Pith_, presseth thence into the Pores of
the _Lignous Body_; so having well fill’d these, is in part by the same
Collateral motion disbursed back into a yet higher Region of the _Pith_.
By which partly, and partly by that portion of the _Sap_, which in its
perpendicular ascent was before lodged therein; ’tis thus here, as in any
inferiour place equally repleat. Whereupon the force and vigour of the
perpendicular motion of the _Sap_ herein will likewise be renew’d; and
so its Collateral motion also, and so its pressure into the Pores of the
_Lignous Body_, and consequently its ascent therein; and so by a pressure
from these into the _Pith_, and from the _Pith_ into these reciprocally
carried on, a most ready and copious ascent of the _Sap_ will be
continued from the bottom to the top, though of the highest _Trunk_.
_An Appendix._
_Of Trunk-Roots and Claspers._
The distinct Parts whereof these are constituted, are the same with those
of the _Trunk_, and but the continuation of them.
_Trunk-Roots_ are of two kinds: Of the one, are those that vegetate by a
direct descent: The place of their Eruption is sometimes all along the
_Trunk_; as in _Mint_, &c. Sometimes only at its utmost point, as in the
_Bramble_.
The other sort are such as neither ascend nor descend, but shoot forth
at right Angles with the _Trunk_; which therefore, though as to their
Office, they are true _Roots_, yet as to their Nature, they area _Middle
thing_ betwixt a _Root_ and a _Trunk_.
_Claspers_, though they are but of one kind, yet their nature is double;
not a mean betwixt that of the _Root_ and that of the _Trunk_, but
a compound of both; as in their Circumvolutions, wherein they often
mutually ascend and descend, is seen.
The use of these Parts may be observed as the _Trunk_ mounts, or as it
trails. In the mounting of the _Trunk_, they are for support and supply:
For support, we see the _Claspers_ of _Vines_; the Branches whereof being
very long, fragile and slender, unless by their _Claspers_ they were
mutually contain’d together, they must needs by their own weight, and
that of their Fruit, undecently fall, and be also liable to frequent
breaking. So that the whole care is divided betwixt the Gardener and
Nature; the Gardener with his Ligaments of Leather secures the main
Branches; and Nature with these of her own finding, secures the less.
Their Conveniency to which end, is seen in their Circumvolutions, a
motion not proper to any other Part: As also in their toughness or
strength, though much more slender than the Branches whereon they are
appendent.
For Supply, we see the _Trunk-Roots_ of _Ivy_: For mounting very high,
and being of a closer Constitution than that of a _Vine_, the _Sap_
could not be sufficiently supplied to the upper Sprouts, unless these
to the _Mother-Root_ were joyntly assistant. Yet serve they for support
likewise; whence they shoot out, not as in _Cresses_, _Brook-lime_, &c.
reciprocally on each side, but commonly all in one; that so they may be
fastened at the nearest hand.
In the Trailing of the _Trunk_, they serve for stabiliment, propagation
and shade. For stabiliment, we see the _Claspers_ of _Cucumbers_: For
the _Trunk_ and _Branches_ being long and fragile, the Brushes of the
Winds would injuriously hoise them to and fro, to the dammage both of
themselves and their tender Fruit, were they not by these Ligaments
brought to good Association and Settlement.
As for this end, so for Propagation, we see the _Trunk-Roots_ of
_Camomile_. Whence we have the reason of the common observation, that it
grows better by being trod upon: the Mould, where too laxe, being thus
made to lie more conveniently about the said _Trunk-Roots_ newly bedded
therein; and is that which we see also effected in Rowling of _Corn_.
For both these ends, we see the _Trunk-Roots_ of _Strawberries_; as
also for shade; for in that we see all _Strawberries_ delight; and by
the trailing of the Plant is well obtain’d: So that as we are wont to
tangle the Twigs of Trees together to make an _Arbour Artificial_; the
same is here done to make a _Natural one_; as likewise by the _Claspers_
of _Cucumbers_: For the Branches of the one by the Linking of their
_Claspers_, and of the other by the Tethering of their _Trunk-Roots_,
being couched together; their tender fruits thus lie under the Umbrage of
a _Bower_ made of their own Leaves.