32 AET. 4. — A. YASUDA : ON THE 



upper, and yet others have none on either surface. Thus in 

 Luffa cylindrica, L. acutangula, Cucumis sativus, C. Melo, 

 Beniiicasa cerifera, Lagenaria vulgaris and Cucurbita Pepo, they 

 are present on both surfaces ; in Melothria japonica and Citrullus 

 vulgaris, only on the upper ; in Aethiostemma raceynomm, Mo- 

 moî'dica Charantia, Trichosanthes cucumeroicles, T. japonica, T. 

 muliiloha and Gymnostemma cissoides, they are entirel}^ absent. 



Pallisade JPat'eiichf/ma. The pallisade pareneliyma of the 

 cotyledons is generally many-layered ; but there are some excep- 

 tional cases, in which the pallisade parenchyma can be scarcely 

 recognised. The commonest type of the pallisade parenchyma 

 consists of two* or three-layered cells : e.g. Actinostemma racemosum 

 Melothria japonica, Luffa cylindrica, L. acutangida, Citrullus 

 vulgaris, Cucumis sativus, C. Melo, Benincasa cerifera, Lagenaria 

 vulgaris, and Cucurbita Pepo. In 3Iomordica Charantia, Tricho- 

 santhes cuGumeroides, T. japonica, T. multiloba and Gymnostemma 

 cissoides the pallisade cells are indistinct. 



Spongy Parenchyma. The layers of the spongy parenchyma- 

 cells of the cotyledons are much more numerous than those of the 

 foliage-leaves. A very peculiar structure of the spongy parenchyma 

 appears in the cotyledons of Actinostemma racemosum where it pre- 

 sents a reticulate appearance, the cells radiating from a fibre- vascular 

 bundle and thus leaving very large intercellular spaces among them, 

 a character which reminds us of the inner structures of water- 

 plants (PI. IV. Fig. 49). The spongy parenchyma- cells of the 

 cotyledons of Momordica Charantia, Trichosanthes cucumeroides, T. 

 japonica, T. multiloba and Gymnostemma cissoides, are not well 

 difierentiated, and possess no marked intercellular spaces. 



