Plate X. 



M.B.T. 



FIG. 23. (Fig. A), Transection of the underground stem of Pterig aquilina. A, 

 Epidermis; B, concentric flhro-vascular bundle; C, band of thick-walled brown 

 sclerenchyma; D, thin-walled parenchyma of the fundamental system; E, xylem of 

 the vascular bundle; F, phloem. (x!7.) 



(Fig. B). Enlarged concentric bundle from (Fig. A). A, bundle sheath; B, D, 

 phloem parenchyma and sieve tissue: C, xylem of the bundle: E, parenchyma cells 

 of the fundamental system forming the main mass of the stem and the "ground 

 work" for the other tissues. (xlOO.) 



