VEGETABLE HISTOLOGY AHD PHYSIOLOGY. 



151 



In the preparation for cell division nucleus-like formations usually appear 

 in the mother cell. The whole protoplasmic body breaks up into two, three, 

 four, or more parts, and each quickly takes on a spher- 

 ical form (Fig. 479). Sacks' 1 Text-book of Botany. 



All these modes of cell multiplica- 

 tion and formation are subject to great 

 variation ; each has a tendency to run 

 into one of the others ; the last is espe- 

 cially liable to vary as to number of 

 daughter cells. 



384. The form of cells varies to 

 suit the use for which they are in- 

 tended and the amount and direction 



479 



479, Showing cell forma- 

 tion in Achlya mother cell, 

 showing a number of nuclei 

 in the mass of protoplasm 

 which is preparing to break 

 up into a number of inde- 

 pendent or daughter cells ; 



of the pressure to which they are sub- a ' a ' a ' etc " nu 

 jected* The normal shape is globular or spheroidal 

 when free from pressure (Fig. 480) ; when pressure 



480, Form of cells in loose parenchyma. 481, Cross-section of parenchyma cells from stalk of Indian 

 Corn (X550), showing form under slight pressure; gw,gw, partition walls ; a, , intercellular spaces. 



from surrounding cells is exerted, they be- 

 come ellipsoidal, egg-shaped, prismatic, or 

 polyhedral (Figs. 481,482). In the trunks 

 and branches of trees and stems of herba- 

 ceous plants the cells become elongated 

 in the direction of growth (Fig. 467). 

 482, Form of ceiis 385. The size of the cells in the soft 



under greater pressure 



from aii directions. tissue varies ; the largest is about -gV of 



