590 



BOTANY 



PART II 



of firm leathery texture and persist for a number of years, alternate with smaller 

 scale leaves and form a large terminal crown. The surface of the cylindrical or 

 tuberous stem is clothed with the scale leaves and the bases of the old foliage 



Fio. 582. Gycas revoluta, female plant in flower. (From a photograph.) 



leaves. Mucilage ducts are present in all parts of the plant. The vascular bundles 

 are collateral, but their xylem consists of tracheides only. 



The Cycadaceae are dioecious. Fig. 582 represents a female plant of Cycas 

 revoluta, in which the growing point forms alternate zones of foliage leaves and 

 macrosporophylls. When young the foliage leaves are rolled up circinately as 

 in the Ferns. One of the sporophylls is represented in detail in Fig. 582a. It 

 shows the pinnate form of the foliage leaf, but is densely covered with brown hairs, 



