COMPAKATIVE ANATOMY OF THE CUCUKBlTACEiE. 11 



cucmneroides, T. japonica, T. multiloba, and Gymnostemma cis- 

 soides ; to the tliird, Cucurbita Pepo. 



The size of the sieve-tubes is so large that it serves as a 

 distinctive character to the family. The following numbers denote 

 the diameters of the large sieve-tubes in the stems of each species; 

 Luffa acutangula 0.0(S8 nmi. 



Cucurbita Pepo 0.088 „ 



Luffa cylimlrica 0.087 „ 



Trichosanthes japonica 0.085 ,, 



Benincasa cerifera, 0.080 ,, 



Lagenavia mdgaris 0.075 ,, 



Movbordica Gharantia 0.075 „ 



Trichosanthea multiloba 0.070 ,, 



T. c lie lime ro id es 0.070 ,, 



Gitrullus vidgaris 0.065 ,, 



Cucumis 31elo 0.005 ,, 



C. sativus 0.065 ,, 



Hchizopepon bryoïiiœfolius, var. japonicas 0.054 „ 

 Actinodemma racemosum 0.045 ,, 



Gymnostemma cissoides 0.040 ,, 



3Ielothria japonica 0.040 ,, 



(b) Xylem. Among the characteristic features of the xylem 

 vessels the following are to be noticed. They are very well- 

 developed and become especially noticeable as the stems advance 

 in age, when they can be easily perceived even with the naked 

 eye. As a rule thyloses^' are developed in old vessels. By com- 

 paring the diameters of the large vessels in each species the 

 following average measurements were obtained : 



1] H. A. LoTAK. loc. cit. p. 30. 



