MORPHOLOGY OF HIGHER PLANTS. 



185 



occurs in leaves and all green parts of the plant, (b) Reserve 

 PARENCHYMA occurs in secds, roots, rhizomes, etc., and contains 

 starch, aleurone grains, fixed oils and other reserve materials. 

 The parenchyma in stems and leaves of various of the orchids, 



Fig. ioi. Forms of cells. A. — Transverse section of the pith of Tradescantia vir- 

 ginica: I, intercelliilar space; W, cell wall. B. — Transverse section of calamus rhizome 

 showing a large oil-secretion cell, smaller cells containing starch, and large intercellular 

 spaces (T). C. — Transverse section of the stem of Phytolacca decandra showing coUenchy- 

 matous cells beneath the epidermis. D. — Longitudinal section of taraxacum root showing 

 branched laticiferous tissue (L). E. — Transverse section of pyrethrum root: R. oil-secre- 

 tion reservoir with oil globules; I, cells with sphere-crystals of inulin, such as separate in 

 alcoholic material-; L,. cells containing irregular masses of inulin, as found in dried material. 

 F. — Ix)ngitudinal section of stem of Cucurbita Pepo; S, sieve-cell with protoplasm-like 

 contents, and transverse walls (sieve plates) showing simple pores. 



as well as that of plants of arid regions, which store water, may 

 be included in this group, (c) Conducting parenchyma assists 

 in the transferral of food from one part of the plant to another. 



