240 



MORPHOLOGY OF GYMNOSPERMS 



THE MICROSPORANGIUM 



The microsporangiate strobili are never terminal on the primary 

 axis or even upon the larger branches (figs. 263-265). Their rela- 

 tion to the axes, foliage leaves, and scales is variable. Sometimes 



Figs. 263-265. — Strobili of araucarians: fig. 263, Agathis australis; staminate 

 (right) and ovulate strobili of same age; fig. 264, Araucaria imhricata; two staminate 

 strobili with a vegetative bud between them; fig. 265, Agathis bornensis; transverse 

 section of sporophyll and pendent microsporangia. — From photographs by Thomson. 



they appear terminal on small leafy shoots of the last order, and 

 sometimes they occur in the axils of the leaves of stronger shoots. In 

 Pinus they replace dwarf shoots in the axils of scales, being usually 

 numerous and forming a cluster beyond which the parent axis 

 continues its growth. 



