COMPARATIVE ANATOMY OF THE CUCURBITACEiE. 37 



in the main roots are tetrarcli.'' In the lateral roots, however, 

 di-, tri- or polyareh bundles are found especially in the adventitious 

 roots : thus, for examj)le, the pentarch occur in those of Actino- 

 stemma racemosum, Jlelothria japonica, Lvffa cylindrica, L. 

 acutangula and Benincasa cerifera ; the hexarch, in those of 

 Trichosanthes cucumeroides, T. japonica, T. multiloba, and Gymno- 

 stemma cissoides ; the octarch, in those of Cucurbita Pepo.'^ In 

 old roots of Momordica Cliarantia the fibro-vascular bundles are 

 arranged in double rows at the angled portions as in the old stem, 

 one small secondary bundle, or occasionally two, being newly formed 

 outside of the primary one. 



(a) Phloem. The sieve-tubes found in the roots are of smaller 

 sizes than those of the stems. The diameters of the large sieve- 

 tubes under consideration are shown in the following table : 

 Lagenaria vulgaris 0.075 mm. 



Beniticasa cerifera 0.070 ,, 



Momordica Charantia 00.70 ,, 



Luffa cylindrica 0.068 ,, 



L. acutangula 0.0G7 ,, 



Cucurbita Pepo 0.067 ,, 



Trichosanthes japonica 0.060 „ 



T. multiloba 0.0Ö8 ,, 



Citrullus vulgaris 0.057 ,, 



Trichosanthes cucumeroides 0.055 ,, 



Cucumis sativus 0.055 ,, 



a 3Ielo 0.054 „ 



Schizopepon bryoniœfoliuSy var. 



japonicus 0.0-10 ,, 



1) 11. A. LoïAR. loc. cU. p. 155. 



2) Ditto, p. 170. 



