Of the Pith of Roots. 249 
parts, from the circumference towards the center of the 
root, and all together conftitute that which is before 
called the infertment. Thefe infertments are moft ob- 
fervable in the roots of many herbs, as comfrey, which 
exhibits a good notion of all other, as well trees as herbs ; 
fometimes this parenchymous body is difpofed into rings, 
as in fennel. In moft woody roots, they ftream between 
the pith and bark, like fo many fmall rays. In fome 
roots they continue to the center, as columbine, in others 
not, as parfnip ; and fometimes different in the fame root, 
asEF in the vine, fig. 471. They are compofed of 
many fmall bladders, as in the bark, but generally 
fmaller. Their fhape ufually round, but fometimes ob¬ 
long and oval, as in borage, or oblong and fquare, as in 
the vine. 
The lignous part alfo confifts of two kinds of bodies, 
fucciferous, or lignous, and air vefiels. The lignous are 
of the nature with thofe of the bark, and in a tranfverfe 
fe&ion of the root, emit a liquor as thofe do. Thefe 
vefiels are no where interwove or braced together, but 
continue from one end of the root to the other. 
The pofition of both thefe kind of vefiels is various, 
the fucciferous or lignous are fometimes fituate in diame¬ 
trical lines, as in the vine, fig. 471. and moft trees, 
fometimes oppofite to the areal, as in beet, &c. 
Of the pith of roots. 
W ithin the woody part, is the pith, which is not 
common to all roots, for fome have none, as ni¬ 
cotian, ftramonium, and others. The pith, for the moft 
part, efpecially in trees, is a fimple body, yet like the 
bark it is compounded, fome fucciferous vefiels being 
mixed with it, as in jerufalem artichoke, horfe-raddifn, 
&e. 
