30 ELEMENTS OF BOTANY. 
starting out as expansions of roots, not of underground stems 
like those of the potato, Fig. 35, and by the irregularity with 
which buds appear on their surface, if they appear at all. 
44. Structure of Roots.— The structure of the very young 
root has been somewhat explained in §§ 17, 18. That of 
older woody roots of dicotyledons is somewhat more com-_ 
plicated. 
Fic. 16.— A Taproot. Fie. 17.— Fibrous Roots. Fic. 18.— Fascicled Roots. 
Cut thin transverse sections! of large and small roots of any hardwood 
tree? and examine them first with a low power of the microscope, as a two- 
inch objective, to get the general disposition of the parts, then with a 
higher power, as the half-inch or quarter-inch, for details. With the low 
power note: 
(a) The brown layer of outer bark. 
(b) The paler layer within this. 
1 These may be cut with a razor, flat-ground on one side and hollow-ground on 
the other, with a scalpel, or with a regular section-knife. The beginner will prob- 
ably find much difficulty in getting good sections, but will at any rate soon obtain 
some which are thin enough on the edges to be fairly transparent. A section of very 
small area will be as good for making out detail of structure as one which extends 
all the way across the root. Unless a good deal of time is available for laboratory 
work, the sections will have to be prepared by the teacher, or they may be bought 
ready-cut. See Appendix C. 
2 Young suckers of cherry, apple, etc., which may be pulled up by the roots, will 
afford excellent material. 
