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. If a 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 (Tab. 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 ofi" 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 squamae, 

 or tooth-shaped scales. Matthiolus {Comm. in Lib. quartum Di- 

 oscoridis, p. 314. edit. Ven. 1583.) evidently took them for roots ; 



" Radice 



