90 FOUNDATIONS OF BOTANY 



Notice that in both types bast fibers and wood fibers are 

 present, but the proportions in (1) and (2) vary greatly. 



103. Kinds of Cells which compose Stems. — The stu- 

 dent has already seen something of cells in the seed, in 

 the roots of seedlings and mature plants, and in several 

 kinds of stems. But he will need to become acquainted 

 with a much larger variety of cells in the stem. The fol- 

 lowing materials will serve to illustrate some of the most 

 important forms.^ 



Examine with a half-inch objective and one-inch eyepiece (or 

 higher power) these preparations (1-9 below) : 



Study very carefully each of the sections described, find in it 

 the kind of cell refen-ed to in the corresponding number (1-9) of 

 the following section (104), and make a good sketch of a group of 

 cells of each kind as actually seen under the microscope.'' 



(1) Very thin sections of the epidermis of a potato, some cnt parallel 

 to the surface (tanr/ential), others cut at right angles to the epidermis. 



(2) Thin sections of the green layer of the bark of Forsythia, 

 spindle tree (Euonymus), or box-elder (Negundo), 



(3) Thin cross-sections and longitudinal sections of the inner bark 

 of linden twigs, or of full-grown stems of flax. 



(4) Longitudinal sections of the stem of squash or cucumber plants. 



(5) Thin cross-sections of young twigs of pine or oak, cut in late 

 summer. 



(6) Thin cross-sections and longitudinal sections, cut from pith 

 toward bark (radial') of young wood of sycamore, of sassafras, or of 

 box-elder. 



(7) Thin longitudinal sections of the stem of castor-oil plant 

 (Ricinus) or of the stalk (peduncle) on which the fruit of the 

 banana is supported. 



1 These studies may be made from sections cut by the pupil, by the teacher, or 

 by a professional hand, as circumstances may dictate. The soft bast (No. 4, see 

 p. 91) can best be studied in good prepared sections obtained of the dealers. 



" Nothing can do so much to make these studies valuable as for the teacher 

 to correct in class the errors of most frequent occurrence in the drawings, by 

 aid of his own camera lucida drawings of the same objects. 



