518 OX SEEDLINGS 



interior of the seed ; cotyledons bilobed and the lobes again bifid 

 with the secondary segments entire or emarginate (in the immature 

 state), slightly auricled at the base ; radicle short, stout, triangular, 

 pointed. 



Pterocarya caucasica, C. A. Mey. 



Fruit sessile, inferior, tipped with four tooth-like perianth-seg- 

 ments, seated in the axil of a small bract, which for more than half 

 its length is adnate to the anterior part of the fruit, with two 

 oblique wings consisting of two enlarged bracteoles adnate to and 

 enclosing more than half of the fruit. 



The wings are obliquely attached to the fruit owing to its 

 ascending direction, and themselves ascend vertically towards the 

 apex of the spike, diverging laterally until they meet those of the 

 contiguous row of fruits on each side. 



Ovary of two carpels, one-celled, but partly two- to four-celled, 

 especially in the lower part ; ovule orthotropous, on an elevated, 

 but really basal placenta formed by the infolding and union of the 

 margins of the carpels. 



A transverse section of the ovary near the base shows four 

 cavities which in the early stage of the fruit are not empty but 

 filled with light, white, spongy or cortical material, becoming dry, 

 brown and easily crushed into little space when the testa of the 

 seed develops. 



The young fruit when examined about the last week of May 

 shows the pistil, subtended at the base anteriorly by a small bract, 

 and at the sides by two bracteoles adnate to its base. Perianth 

 leaves four, inserted on the neck of the pistil a short way beneath 

 the two large spreading coarsely papillose stigmas. The cavity of 

 the ovary is small and nearly filled by the minute ovule. The tissues 

 surrounding the ovule are all coloured alike, and no cavities or 

 cortical tissue are seen. 



By the llth of June all parts of the young fruit have increased 

 very much in thickness, but not much in length. The ovule is much 

 larger, with the distinctly discernible coat slightly overtopping it. 

 The ovary is much wider, and at its base (in longitudinal section) 

 are two whitish masses of tissue, definite in outline and almost 

 colourless, as if the protoplasm had been removed, leaving nothing 

 but water in the cells. 



By the 25th of June the young fruit has increased greatly in both 

 length and breadth. The bracteoles are larger, and the space be- 

 tween the base of the fruit and the ovule has elongated. The chief 

 difference, however, is in the coat of the ovule, which is now twice 



