ELEMENTARY ORGANS. 



Spheroidal cellular tissue is merenchyma 4 , or spharendtyma ; conical, conenchy- 

 ma 5 ; oval, ovenchynui 6 ; fusiform, atractenchyma ; cylindrical, cylindrenchyma 8 ; 

 sinuous, colpenckyma 9 ; branched, cladenchyma w ; prismatical, prismenchyma, 

 which, when compressed, becomes muriform 7 ; stellate, actinenchyma 1 *; entan- 

 gled, branched and tubular, d(edalencliyma n . 



=-.<#4 



17. Parenchyma constitutes all the pulpy parts; the me- 

 dulla or pith (98), the medullary rays (132), a portion of the 

 bark (120), and all that intervenes between the veins of leaves 

 and other appendages of the axis. Consequently it occurs in 

 every part of a plant, and especially in those which are succu- 

 lent. It, however, sometimes acquires, by the deposit of scle- 

 rogen (13), excessive hardness, as in the stone of fruits 3 , and 

 the bony skin of some seeds. 



destines are large cells of Parenchyma, in which raphides (60 a) are often de- 

 posited. 



18. Prosenchyma is confined to the bark and wood, in 

 which it only occasionally occurs. 



19. Besides these a spiral line is often found in the inside of 

 a cell, when fibro-cellular tissue 13 , or inenchyma, is produced ; 

 and it sometimes happens that the membrane connecting such 

 fibres is absorbed, leaving the fibres only to constitute the 

 cell. 



20. The function of the cellular tissue is to transmit fluids 

 in all directions ; the membrane of which it is composed is 

 therefore permeable, although not in general furnished with 



B 2 



