ANA 
But thofe plants that are endued with a confpicuous 
root, and more obvious to the fenfes, differ among 
themfelves very much in this part : for feme are bul- 
bous, fome are fquamous, or tuberous, others gru- 
mous, others fibrous, and laftly, others nodous ; 
which, as it will be fufficient to have taken notice of 
the primary differences of roots, I flaall omit their 
particular definition in this place, and refer them to their 
feveral heads, where each of them fliall be particu- 
larly defcribed. 
The firft part of the root, which is called the Epi- 
dermis, or cuticle, is, for the moft part, of a brown 
or dufky colour, very thin, and eahly peeled off from 
the under fkin (if it be firft foaked in warm water) ; 
which being viewed by a microfcope, fhews its moft 
tender ftrudture much like a net pierced through with 
many fmall hoies. And thefe little orifices of the 
epidermis being dilated, and filled with the received 
moifture, refembling veiicles, which, being exhaufted 
yearly by the mutation of the air, become confoli- 
dated, and perifh •, to wit, this being driven out by 
a new cuticle growing under it, after the fame man- 
ner as fquammigerous animals annually caft the old 
epidermis, a new cuticle coming under it ; fo that 
thefe little veffels, fibrils, or by what name fbever they 
are called, may not unfitly be compared to the veins 
of animals. 
But the other part, which on the outfide conftitutes 
the cortex, or outer bark, and on the infide the li- 
ber, or inner bark, is called cutis •, in which there 
are parts to be confidered of a four-fold kind. 
1 . Certain ftrong fibres, cohering and elaftic, ftretched 
out vertically with the lateral fibres communicating 
among themfelves, and compacting, or thrufting in 
the former, they form a hollow cylinder* or zone, 
under the epidermis * and this hath another under it, 
which alfo includes a third * and fo of the reft, to the 
moft inward of all, which luxuriates near the wood, 
and is by a peculiar name called liber, or inward bark. 
And thefe zones, or girdles, although they are moft 
innumerable, may all be peeled off as the lamellae of 
bulbs, when the lap flows through them * and inaf- 
much as thofe fibres in the harder roots of trees are 
almoft of a bony nature, they procure a firmnefs to 
the cortex or outward bark * and thefe fibres are in 
all plants, and appear as well in grafs as in the Cedar 
tree, although they are more compaft in trees, than 
in plants of a tenderer ftru&ure, which are more eafily 
fuftained. 
2. In the areas, or fpaces, which are between the fi- 
bres and their anaftomofes, there are every where 
membranaceous veffels full of moifture, or little utri- 
cles, which, in the arete, or intercepted fpaces that 
are of a different figure, are found to be various, and 
accommodated to all the fpaces ; but all thefe utri- 
cles communicate among themfelves, as is beft feen 
in the greater celandine, when we fqueeze out that 
golden coloured liquor with which it is filled * and 
the middle fpaces betwixt thefe zones have like utri- 
cles, and all the fibres conftitute hollow canals •, but 
the utricles have receptacles communicating among 
themfelves. 
3. Aereal veffels, or tracheae, are open from the 
lower to the upper part of the plant, and are twifted 
or curled after an admirable manner, and dilpofed 
round about with fibres and utricles in form almoft of 
a fpital line, which in their cavities contain an elaftic 
air * which being affeded by the external air, firft ex- 
panded, and afterwards condenfed, will be changed 
after a like manner, and feel the fame viciffitudes of 
cold and heat, and will undergo a reciprocal motion 
of cold and heat. This adion is exerted in the vef- 
fels filled with moifture, which when they cannot be 
condenfed, give place, and are driven to thofe that 
are higher, and are moved forward. 
4. Laftly, befides fibres, utricles, and tracheae, a 
peculiar kind of veffels appear, containing the moi- 
ftures, as it feems fecreted by the organical difpofi- 
tion of the plant itfelf, which water, or molften not 
only the cortex, but the wood, and the reft of the 
ANA 
parts of vegetables, and are turgid with a conceded 
juice, which feems far more elaborate than is the 
moifture contained in the fibres or utricles * and the 
mouths of thefe veffels being of a different figure, 
pour forth fometimes a various liquor, according to 
its. peculiar nature, chiefly near the outward region of 
the cortex; fo the Tithymalus and Cichory com- 
monly diftil a milky humour, and the Cyprefs, Fir, 
and Pine, a certain fpecies of turpentine. 
And by how much thefe circles are more outward, 
by fo much the middle fpaces between the two zones 
are greater ; and are leffened always towards the more 
inward in a certain, proportion, which feems to de- 
pend on this, viz. the outward air ading on all fides 
with an equal preffure, and by a certain power preffes 
the fecond ; and this alfo by this means, is preffed by 
its own condenfed air, and prefies together thofe 
which are more inward, becaufe it cannot exert its 
force upon the external air ; therefore the fecond cir- 
cle is neceffarily more compreffed than the firft, and 
the third more than the fecond, and fo of the reft. 
And the utricles placed between the circles are preffed 
by the fame proportion ; which, by degrees, are more 
and more exhaufted; thence the inner circle lofes 
moft of all the compreffed and condenfated utricles, 
and by degrees grows folid. 
And this is properly called Liber (the inward bark), 
and is that circle, which, being middlemoft by place 
and nature, between the cortex, or outward bark, 
and the wood, comes neareft to the nature of the 
wood, and in time paffes into it ; for the cortex lofes 
every year one fuch circle, and becomes wood, which 
may be diftinguifhed from the former circles of the 
root, flock, or trunk ; and if they are cut horizon- 
tally, will fhew the number of fuch circles, and how 
many years the tree is old. 
And this fucceflive mutation of the cortex into li- 
ber, and of liber into wood, is like to that we ob- 
ferve in the human body in the beginning of a cal- 
lus ; for a callus confifts of fkin, but fo compreffed,' 
that all the veffels are loft ; and that fkin, being be- 
come folid, is increafed, and grows to a greater bulk. 
But befides thefe hitherto defcribed, there occur cer- 
tain peculiar veffels (of which mention has been made 
in deferibing the cortex), which are found full of 
turpentine, gum, or a certain concreted juice proper 
to them ; the conllant progrefs of which is not very 
confpicuous in all of them, by reafon of the tranfpa- 
rency of the moifture. 
5. The fifth and laft part is the moft inward, the 
medulla or pith, difpofed in the middle center of the 
root ; and as it feems different from the former, fee- 
ing this is fometimes wafted, and that never, this ap- 
pears more fungous, that more durable. 
As to the manner of the root’s performing its func- 
tion, it may be obferved, that the root having im- 
bibed the faline and aqueous juices of the earth, and 
faturated itfelf with them, for the nourifhment of the 
tree, thofe juices are put into motion by heat ; -which 
having entered the mouths of the arterial veffels from 
the root, they mount to the top with a force anfwer- 
able to what lets them in motion ; and, by this means, 
they gradually open the minute veffels rolled up, and 
expand them into leaves. 
2. The wood ; this is confidered as confifting of ca- 
pillary tubes, running parallel from the root through- 
out the ftalk. Some call the capillary tubes arterial 
veffels, becaufe the fap rifes from the root through 
thefe. The aperture of thefe tubes are, for the moft 
part, too minute to be perceived by the bare eye, un~ 
lefs in a piece of charcoal, cane, or the like. 
Wood, lays Dr. Grew, by microfeopical obfervati- 
ons, appears to be only an affemblage of infinitely 
minute canals, or hollow fibres, fome of which arife 
from the root upwards, and are difpofed in form of 
a circle ; and the others, which are called infertions, 
tend horizontally from the furface to the center, fo 
that they croft each other, and. are interwoven: like the, 
threads of a weaver’s web. 
Befides 
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