*38 B O T 
generally difpofed ifl collateral vows running longitudinally 
through the root. Some of thefe contain air, others fap. 
The pit'll is the centrical part of the root. Some roots 
have no pith, as the wormwood, tobacco, &c. others 
have little or none at the extremities of the roots, but 
have a confiderable quantity of it near tiie top. The pith, 
like every other part of a plant, is derived from the feed ; 
but in Conic it is more immediately derived front the bark: 
For file infertions of the bark, running in betwixt the rays 
of the wood, meet in the ,centre, and conftiture the pith. 
It is owing to this circumftance, that, among roots which 
have no pith in their lower parts, they are amply provided 
with it towards the top, as in columbine, lovage, &c. The 
bladders of the pith are of very different fizes, and gene¬ 
rally of a circular figure. Their pofition is snore uniform 
than in the bark. Their Tides are not mere films, but a 
compolition of (mall fibres or threads ; which gives the 
pith, when viewed with a microfcope, the appearance of 
a piece of fine gauze or net-work. Thus we fee, the whole 
fubftance of a root is nothing but a congeries of tabes and 
fibres, adapted by nature for the abforption of nourifhment, 
and ot courfe for the extension and augmentation of the 
vyhole plant. To illudrate what has been here fhited, we 
have (hewn, in the annexed Botanical Plate, at fig. i. a 
tranfverfe febtion of a root ot wormwood, as it appears to 
the naked eye. Fig. 2. is a feblion of the fame, magnified ; 
a a, the (kin, with its vefiels; b b, the bark; the round 
holes, c c, &c. are the Iymph-dn£ts of the bark: all the 
other holes are little cells and Tap-vefiels. At da are 
(hewn parenchymatous infections from the bark, with the 
cells, &c. The rays of the wood are reprefented at ee, in 
which the holes are the air-vefiels. 
Roots are divifible into two parts, viz. the caudex, or 
body of the root; and the radicula , radicle, or little root. 
The caudex, or body of the root, both alcends and defeends. 
The attending caudex raifes itfelf gradually above ground, 
ferving often as a trunk, and produces the herb or plant; 
and it is from hence Linnaeus infers, that all trees and 
ihrubs are to be confidered as roots above ground ; becaufe 
trees, if inverted, will put forth leaves from the defeending 
caudex, and roots from the afeending; fo that the branches 
become roots, and the roots branches. The defeending 
caudex ftrikes gradually downward into the ground, and 
is terminated by the radicula, or radicles, which are the 
fibres of the root, aCting as fo many mouths or channels 
whereby the nourifhment is drawn into the body ot the 
root, as into the ftontach of man, and thence communi¬ 
cated to the remoteft parts. 
A root is alfo difiinguifiied, according to its direction and 
firuTure; into Perpendicular, when it runs directly down¬ 
wards. Horizontal, when it extends itfelf tranfverfely under 
the earth. Simple, when it has no fubdivifions. Ramous, 
when it is divided into lateral branches. Fujiform, when 
it is oblong, thick, and tapering. Tuberofc, when it con¬ 
fifts of roundifii bodies collected into a bunch ; and thefe 
are either knobbed, palmated, fafciculated, or pendulous. 
Repent or creeping, when it runs out to a diftance, and 
puts forth radicles from fpace to fpace. Fibrous, when it 
confifts only of fibres or filaments. Prccmorfe, when the 
termination is blunt, or not tapering. Articulate, when 
the radicles are jointed. Dentate, when formed like teeth. 
Bulbous, when confiding of a bulb ; and thefe are either 
fquamous or fcaly, tunicate or coated, globe-fiiaped, folid, 
and tefticulate or double. In order more completely to 
illuftrate the fubjedt, a correct figure of each of thefe 
roots is given in the annexed Botanical Plate 1 . Fig. 3. 
is a fibrous root, confiding of filaments only, as in vernal 
grafs. 4. A ramous root, which, like the trees and (hrubs, 
fubdivides into branching fibres. 5. A fufiform or fpindle- 
(haped root, gradually lefiening downward, as fpring rad- 
difit. 6. A prsemorfe root, as if bitten oft’, when the lower 
part is truncate, and the termination not tapering; as in 
plantain, fcabious, and valerian. 7. A repent, or creeping 
root, creeping horizontally underground, as the flowering 
rufh, 8, An articulated or jointed root, divided into joints, 
ANY. 
as couch-grafs. A dentated root, compofed of articu¬ 
lations like teeth, as toofhwort. 10. A tuberous root* 
carnous or knobby, connected together by (lender fibres, 
as piony. 11. A fafciculated root, fleftiy and (eftile at the 
bale of the f'ootftalk of the leaves, as ranunculus. 12. A 
palmated root, lhaped like a hand, as broad-leafed orchis. 
13. A granulated pendulous root, havirtg gram -1 ike fub- 
ftances difperfed on the fibres, as wood-forrel. 14. A fqua¬ 
mous or fcaly bulbous root, as white lily. 15. A tuni- 
catcd or coated bulbous,root, as daffodil, and onion. 16. A 
globe-fhaped (olid bulbous root, as the butter cup. 17. A 
tefticuhyted, two-lobed, or double bulbous root, as two¬ 
leaved orchis. 
Of the TRUNK or STEM. 
The trunk, or Item, is that part of a plant ariling out 
of the root, and which fu(tains the leaves, flowers, fruits. 
See. Like tire root, .it confifts of three parts, viz. the bark, 
wood, and pith. Thefe parrs; though fubftarvtially the 
lame in the Trunk as in the root, are in many cafes very 
different in their texture .and appearance. The (kin of the 
bark of the trunk is corupofed of very minute bladders, 
interiperled with longitudinal woody fibres, as in the net¬ 
tle, thiftle, and molt herbs. The outfide of the (kin is 
vifibly porous in fame plants, particularly the cane. The 
principal body of the bark is compofed of parenchyma, 
and i nnumerable vefiels much larger than thole of the (kin. 
The texture of the pulpy part, though the fame fubftance 
with the parenchyma in yoots, yet (eldom appears in the 
form of rays running towards the pith ; and when they do 
appear, they do not extend above half way to the circum¬ 
ference. The vefiels of the bark are very differently litua- 
ted, and deftmed for various purpofes in different plants. 
For example, in the bark of the pine, the inmoft are lyrnph- 
dutls, and exceedingly fmall; the outmoft are gum or re- 
finiferous vefiels, deftined for the feevetion of turpentine; 
and are fo large as to be diftinCtly viffblc to the naked eye. 
The wood lies between the bark and the pith, and con¬ 
fifts of a parenchymatous, and a ligneous part. In all trees, 
the parenchymatons part of the wood, though much diver- 
lified as to (ize and confidence, is uniformly dilpofed in 
diametrical rays, or infertions running betwixt fimilar rays- 
of the ligneous part. The true wood is nothing but a con¬ 
geries of old dried lymph-duels.' Between the bark at>d 
the wood a new ring of thefe du6ts is formed every year, 
which gradually lofes its fo ft ne Is as the cold feafon ap¬ 
proaches, and towards the middle of winter is condenfed 
into a folid ring of wood. Thefe annual rings, which are 
diftindtly vilible in mod trees when cut through, feive as 
natural marks to diffinguifh their age. The rings of one 
year are fometimes larger, fometimes lefs, than thofe of 
another, probably owing to the favourablenefs or unfavour- 
ablenefs of the feafon. 
The pith, though of a different texture, is exaftly of the 
fame fubftance with the parenchyma of the bark, and the 
infertions of the wood. The quantity of pitlt is various in 
different plants. Inftead of being increafed every year like 
the wood, it is annually diminiftied, its vefiels drying up, 
and affiuning the appearance and ftrufhire of wood ; inlo- 
nnich that in old treels there is fcarcely fuch a thing as pith 
to be difeerned. A ring of fap-velfel's is ufually placed 
at the outer edge of the pith, next the wood. In the pine, 
fig', and walnut, they are very large. The parenchyma of 
the pith is compofed of fmall cells or bladders, of the fame 
kind with thofe of the bark, only of a larger fize. The 
general figure of thefe bladders is circular; but in fome 
plants, as the thiftle and borage, they arc angular. Though 
the pith is originally one connedled chain of bladders, yet 
as the plant grows old they fhrivel, and open in different 
directions. In the walnut, after a certain age, it appears 
in the form of a regular tranfverfe hollow divilion. In 
fome plants it is altogether wanting; in. others, as the 
fonchus, nettle, &c. there is only a tranfverfe partition of 
it at every joint. Thefe carious properties of the trunk 
are reprefented in the Botanical Plate II. where fig. s. 
(hews a tranfverfe feftion of a branch of afh, as it appears 
to 
