74 



BOTANY AND PHARMACOGNOSY. 



cones consisting of microsporophylls (stamens) are more or less 

 elongated and cylindrical (Fig. 47, C). The carpellate cones 

 consisting of megasporophylls (carpels) have a shorter longi- 

 tudinal axis, and the cones vary considerably in the different 

 groups (Fig. 47, A, B). 



The Microsporophylls (Fig. 48) are usually of a yellowish- 

 brown color, and consist of a slender stalk and a lamina which 



),/"' 





Fig. 48. A, longitudinal section of cone composed ui ^^^^^ruop^/i. 

 pines; B, longitudinal section of microsporophyll showing microsporangium (pollen sac); 

 C, the same in transverse section showing both microsporangia; D, winged microspore 

 (pollen grain), with a two-celled male gametophyte, the upper cell being the generative 

 cell, the remaining nucleated cell giving rise to the pollen tube. — ^After Schimper. 



bears the microsporangia (pollen sacs) on the lower or dorsal 

 surface (Fig. 48, B, C). In this they show a resemblance to 

 ferns where the sori are borne on the under surface of the leaves. 

 The microsporangia vary in number from 2 to 15, and are pro- 

 tected in various ways, either being sunk in the tissues of the sporo- 

 phyll,asinPn;?/.y and Abies or they are, as in luniperns and Thuja, 

 provided with a covering resembling the indusium of the sori of 

 the ferns. The walls are variously ■ thickened and on drying, 



