STRUCTURE OF THE PLANT-CELL 5 



known as chloroplasts. On examining a k-af of the Canadian 

 Pondweed [Elodea canadensis) under the high power, each of 

 the more or less rectangular cells will be found to contain a 

 number of chloroplasts, which will be seen from one of two 

 aspects (Fig. 3). Some, situated along the sides of the cell, 

 are ^•iewed in profile and appear as flattened ellipses {OS.). 



Fig. 2. — Staminal hairs of the Spiderwort (Tradescanlia). A, a single 

 hair ; B, a single cell showing the nucleus and strands of cytoplasm 

 passing across the vacuole ; C, a hair plasmolysed with sea-water. 



whilst others hing against the upper or lower walls, and conse- 

 quently seen from the surface, present a round or oval form {Sit.). 

 Each chloroplast is thus a solid body which has more or less 

 the shape of a biconvex lens. 



If attention be centred on a sin,gle cell, the chloroplasts lying 

 against the upper face can be brought clearly into view by 

 turning the fine adjustment ; on focussing to a lower level. 



