49 



The Pines of Australia. 



Figure 28. — Longitudinal section through C amentum and subtending 

 whorls of leaves, illustrating the orthotropous character of 

 the ovules on the sporopliylis prior to thickening. C. 

 Mttelleri, x 13. 



Figure 29. — Longitudinal section through 9 amentum. The thickening 

 on the ventral surfaces of the sporophyll — shown on the 

 right at the top — is just commencing, and one large and two 

 small oil cavities in this sporophyll are cut longitudinally. 

 C. Muelleri, x 21. 



figure 30. — Longitudinal section through '^ amentum showing gynmo- 

 spermous orthotropous ovules and the development of 

 the inner portion of the sporophylls to form the enclosing 

 dome after fertilisation. C Muelleri, x 21. 



Sections illustrating the growth of the ventral side of the sporophylls, until a dome is formed over 



the zygotes, 

 D 



