89 



petioles, cotyledons, tendrils, roots, fruits, and seeds of the above plants, 

 and when necessary old as well as young specimens were examined and 

 compared. Here, however, instead of entering into detailed descriptions, 

 I will give the chief results of my investigation piece by piece as a pre- 

 liminary note. 



(1) The old stems of Luffa and Momordica are very characteristic. 

 They have a sharp keel along the angled portions. The microscopical ex- 

 amination shows that the ridges of Luffa consist only of the outgrowth of 

 the collenchyma, while those of Momordica are formed by newly developed 

 secondary fibro- vascular bundles. 



(2) There are four types 1 ) of the distribution of the sieve-tulles in 

 the stems : a) the vascular-bundle sieve-tubes, b) the ectocyclic sieve-tubes, c) 

 the entocyclic sieve-tubes, and d) the commissural sieve-tubes. Luffa, 

 Momordica, Gymnostemma, and Actinostemma have those of the first and 

 third types ; Lagenaria, Benincasa, Cucumis, Trichosanthes , Citrullus, 

 Schizopepon, and Melolhria those of the first, third, and fourth types ; and 

 Cucurbita all kinds of them. 



(3) Khizomes occur in Melothria and Gymnostemma. They are long 

 and thick, having scales at several nodes and are full of starch-grains, of 

 which those of Gymnostemma are the largest (0.06 mm. in diameter) among 

 the starch-grains contained in any organs of Cucurbitacem. 



(4) . The number of the flbro-vascular bundles in the hypocotyls is 

 generally six, 3 ) except in Citrullus and Cucurbita, the former of which 

 has twelve, and the latter ten. 



(5) The epidermal cells on the upper surface of the blades of Tri- 

 chosanthes cucumeroides are elongated into conical papillaa. 



(6) The epidermis of the blades may be many-layered as in Cucur- 

 bita, a character which is limited to this genus. Momordica contains 

 globular cystoliths 3 ) in the greatly enlarged epidermal cells on the lower 

 surface of the blade. They are united into groups. 



(7) Stomata on the upper surface of the blades are rarely found in 

 Momordica charantia and Trichosanthes japonica, while they are entirely 

 wanting in Schizopepon and Gymnostemma. 



(8) The mesophyH of Actinostemma is very rich in intercellular space*, 

 so that it reminds us of the leaf-tissue of water plants. 



') Compare the work of A. Fischer. Inc. cit. p. 104-108. 



2 ) Henri-Aime Lotae. he. tit. p. 14. 



3 ) O. Penzig. he til. p. 393. 



