8 AET. 4. A. YASUDA : ON THE 



of the stems, and often in the fnrrows between the angles. For 

 example, Actinostemma racemoswriy 3Ielothria japonica, Momordica 

 charantia, Lagenavia mil gar is, Trichosanihes curwneroides, T. 

 japonica, T. multiloba, and Gymnostcmma cissoides have the eol- 

 lenchyma developed only at the angles ; while Luffa cylindrical 

 L. acutangula, Citrullus vulgaris, Cucumis saiivus, C. Melo, 

 Benincasa cerifera, and Cucurbita Pepo have it at the angles as 

 well as in the fnrrows. The number of groups of collenchymatons 

 cells developed in the furrows varies from two to five. Cucumis 

 saiivus and C. Melo have only traces of this tissue in each furrow ; 

 Luffa cylindrica and L. acutangula have two masses of it ; 

 Citrulhis vulgaris and Benincasa cerifera, three masses ; and 

 Cucurbita Pepo, five masses. 



The layers of the collenchymatous cells are much thicker at 

 the angles than in the furrows. Their maximum number (sixteen) 

 is found in the angled portions of the stem of Ljiffa cylindrica, 

 while their minimum number (one) is found in the furrowed 

 portions of the stem of Cucumis Melo. 



Selevenchym a . In young stems the sclerenchyma forms a 

 ring,^^ but when the stems become old the ring breaks up into 

 several sections, so that the latter are placed outward of each 

 fibro-vascular bundle. In some old stems the sclerench3ana is 

 also formed inside of the inner j^hloëm. In other stems a 

 secondarily formed sclerenchyma is developed within the primary 

 one. The secondary sclerenchymatous cells are short and thick- 

 walled, manifesting many pore-canals ; while the primary ones 

 are long and fibre-like. 



1) E. G. O. Müller. Cucurbitaceen in Englejî und Prantl's die natürlichen Pflanzen- 

 familien. 1894. Th. IV, Abt. 5. p. .3. 



