10 ART. 4. A. YASUDA I ON THE 



of the inner ring often gi'ow irregnlai'ly, and in some cases one or 

 two of them are wanting. The old stems of llomordica Charantia 

 and Actinostemma racemo^um present a cliaraeteristie arrangement 

 of the fibro- vascular bundles. We may o])serve doable bundles 

 overlapping one another at the angled portions; i.e., the secondary 

 bundles grow outside of the primary ones from a secondary 

 meristem, so that the angled portions are raised into keels. 



(a) Phloem. The fibro-vascular bundles are of a bicollateral 

 type, so tliey have two kinds of phloem, tlie peripheral and the 

 axial, of which the former is always better-developed than the latter. 



Sieve-tubes occur not only in the phloem but also outside 

 of it. They are, according to Fischer,^^ chxssified under four 

 heads : (i.) vaseular-l)undle sieve-tul)es, winch are found in the 

 phloem; (ii.) ectocyclic sieve-tubes, between the epidermis and the 

 sclerenchymatous ring; (iii.) entocyclic sieve-tul)es, within scleren- 

 chymatous ring ; (iv.) commissural^sieve-tul)es, serving to connect 

 the other kinds of sieve-tubes with one another. 



In reference to the mode of distribution of these four kinds 

 of sieve-tubes we may distinguish three types in the Cucurbitaceœ : 

 the first type has the vascular-bundle and entocyclic sieve-tubes, 

 but no ectocyclic or commissural ones ; the second has the vascular- 

 bundle, entocyclic and commissural sieve-tubes, but lacks the 

 ectocyclic tubes ; the third has the vascular-bundle, ectocyclic, 

 entocyclic, and commissural sieve-tubes. To the first type belong 

 Luffa eylindrica and L. acutancjula ; to the second, Actinostemma 

 racemosum, Melothria ja,ponica, Schizopepon hryoniœfolius, var, 

 japonîcus, 3Iomordica Charantia, CitruUus vulgaris, Oiieumis sativus, 

 C. 3felo, Benincasa, cerifera, Lageyiaria vulgaris, Trichosanthes 



1) A, Fischer. Inc. dl. p. 104. 



