SECRETION RE8ER VOIRS. 



131 



but slightly different developments of the same organ (Fig. 

 117). 



(a) The smaller and more irregular intercellular spaces may be 

 studied in the fundamental tissue of the stem of Indian corn, in the 

 parenchyma of most leaves, and the stems of Juncm. 



FIG. 116. 



Fm. 117. 



Fig. 116. Internal glands of the leaf of Dictamnw fraxineUa. A and B, curly 

 stages of development; C, mature gland ; d, epidermis ; c, p, mother-cells of the ue- 

 creting cells ; o, drop of ethereal oil. After Rauter. 



Fig. 117. Glandular hair of the inflorescence of Dictamnus fraxineUa ; A and B, 

 earliest stages, showing the origin to be similar to that of the internal glands ; C, fully 

 developed hair ; the part h is the true hair, while all below it, including the oil cav- 

 ity, is to be regarded as an outgrowth of the sub-epidermal cells. X about 220. After 

 Rauter. 



(6) Thin cross-sections of the etems and petioles of NymphcKfi, 

 Nuphar, Ndumbium, Sagittaria, Potamogeton, and many other water 

 plants, afford excellent specimens for the study of intercellular canals. 



