JUGLANDEJE 



509 



patches of colourless tissue, which in a longitudinal section 

 appear more elongated. In them the tissue is commencing 

 to disintegrate, while round them, on the contrary, it is be- 

 coming distinctly sclerenchymatous. From the development 

 of the lower part of the fruit, especially on the posterior side, 

 the posterior portion of each bracteole appears to be nearly on 

 the summit of the fruit, the anterior portion being rather 

 lower down. 



Fig. 658 is a longitudinal section taken on August 8. It 

 passes through two of the masses of loose tissue mentioned 

 above, which now form cavities ; while, on the other hand, 

 the surrounding tissues have become much denser, leaving, 



FIG. G5.S. Pterocarya caucasica, x 8 : 

 Va, Va, vascular tissue ; Co', Co, 

 masses of solid cortical tissue ; Co, 

 Co, cavities. 



FIG. 059. Pterocarya caucasica. 

 Longitudinal section of more 

 advanced fruit, x 8. Sept. 1. 

 T, testa ; En, endosperm ; Em, 

 embryo ; P, perianth ; Va, vas- 

 cular tissue; Co, small cavity 

 not yet filled by the seed. 



however, oval spaces of cortical tissue shown in section at 

 Co', Co'. 



The ovary has not materially altered, and the ovule is 

 still very small. 



A few days later, however, the ovule has grown considerably 

 and nearly fills the cavities. Fig. 659 shows a longitudinal 

 section taken on September 1. T is the testa, showing that 

 the seed has now assumed its four-lobed form, though it has 

 not yet quite filled the cavities in the fruit. The greater part, 

 however, is occupied by endosperm, the embryo (Em) being 

 still comparatively small. 



Fig. 660 represents a transverse section near the base of the 

 fruit, taken on September 21, when the fruit and embryo had 



