74 



BOTANY AND PHARMACOGNOSY. 



cones consisting of microsporophylls (stamens) are more or less 

 elongated and cylindrical or ovoid (Fig. 48, A). The carpellate 

 cones consisting of megasporophylls (carpels) have a shorter 

 longitudinal axis, and the cones vary considerably in the different 

 groups. 



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 of microsporophylls, of one of the 

 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,asinP///z/^ and Abies or they are, as in Junipenis and Thuja, 

 provided with a covering resembling the indusiimi of the sori of 

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



