408 Mr. Bowman on the Parasitical Connection 
like the radical fibres of trees and perennial plants. This opinion 
is strengthened, from a larger portion of those which I have ex- 
amined in October and November having had taps inserted into 
the returning vessels of the alburnum, than those I have ex- 
amined in the spring, the greater number of which had short 
or imperfect taps, and were often without the interior system of 
beaded vessels. Ifa root on which they have fixed be carefully 
examined, some minute scars may be observed on the bark, each 
divided, by a straight fissure with prominent lips, into two equal 
parts. These are the cicatrized wounds caused by old and de- 
cayed tubers, some of which may be seen of the natural size on 
the broken extremity of the Ash root (Tas. XXII. Fig. 3. a) ; 
and a magnified transverse section of one, with the cavities 
within, surrounded by its margin of new liber, at Fig. 5. 
The organization of the large tubers of the caudex differs 
from that of the small ones of the extremities, in having a more 
crowded system of beaded and nearly parallel vessels (instead 
of: the central intersecting set of the latter) distributed through 
its whole substance. ‘These vessels are intersected by:a dark- 
coloured regular cone, in the situation represented in the longi- 
tudinal section (Tab. XXII. Fig. 4.), which seems to consist only 
of a more dense assemblage of the vessels themselves, and whose 
entire figure would be that of the concave bottom of a glass bot- 
tle. A cross section of this tuber exhibited its numerous vessels 
in detached spots. The tap was broken off in the root of the 
stock, but its situation is indicated by the letter a. 
I now pass on to that portion of this singular plant from 
which it: has severally been called Dentaria, Squamaria, and 
‘Toothwort, and whose true character seems to have puzzled 
both the older and more modern botanists ; I mean the squamze, 
or tooth-shaped scales. Matthiolus (Comm. in Lib. quartum Di- 
oscoridis, p. 314: edit. Ven. 1583.) evidently took them for roots ; 
** Radiee 
e. 
