Collenchvnia 



Parenchyma 



:-- Xvlem 



Cambium 



Vascular bundle 



Sclerenchyma 

 Pith ray 



Stoma 



Endodermis ^-' 



-,-'-' Sclerenchyma 



-} Epidermis 



Fig. 19. — Features of Angiosperms. A, diagram of section of flower at time of 

 fertilization, showing pollen grains (greatly magnified) germinating on the stigma 

 and pollen tubes growing down towards oyules (seen in centre). Ranged around 

 are the stamens, the large attractiye petals, and the sepals which protected them 

 when in bud. B, cross section of stem of a monocotyledonous Angiosperm {Zea 

 mays) ( about 30); the dark oyal areas are sections of yascular bundles which 

 are characteristically scattered (instead of being disposed in a more or less peri- 

 pheral ring, as in most Dicotyledons). C, diagram of portion of stem of a dicoty- 

 ledonous Angiosperm dissected in cross, radial, and tangential sections to show 

 the yarious tissues of which it is composed ( about 80, but not all parts to precisely 



same scale). 



71 



