28 AKT. 4. A. YASUDA : ON THE 



Ti'iclionics. The petioles may bear several kinds of trichomes 

 or tliey may be nearly smooth. Momordica Cliarantia, Luffa 

 cylindrica, L. acutangula, CUridlus vulgaris, Cucumis sativus, C. 

 3ïelo, Benincasa cerifera, Lagenaria vulgaris, Trichosanihes 

 cucumeroides and Ciwurhiia Pepo, belong to the first group ; 

 Aciinosiemma racemosum, Jleloihria japonica, Scliizopcpon hnjo- 

 niœfolius, var. japonicus, Trichosanihes japojiica, T. mulliloba 

 and Oymnostemma cissoidcs, to the second. 



Collenchy^na. In the middle portion of the jietioles the 

 collenchyma is developed outside of each fibro-vascular bundle. 

 The number of the collenchyma groups varies from five to 

 thirteen, the extremes being represented respectively by Gymno- 

 sLemma cissoidcs and Cucurbita Pepo. In the distal as well as 

 the proximal portions of the petioles several isolated collenchyma 

 groups are united with one another, and in an extreme case all 

 the groups of the collenchyma are entirely fused together. 



Ht'lereitc/i!fnn(. On the outside of each fibro-vascular bundle 

 several-layered sclerenchymatous cells are formed, which are 

 particularly well-developed in Lujfa cylindrica and L. acutangida. 



Fibvo-vascular J iu miles. The fil)ro-Viiscular bundles of the 

 petioles have a circular arrangement. They are always in pairs 

 laterally, while the undermost bundle is unpaired. Sometimes 

 there appears a small bundle in the fundamental tissue under 

 the groove. The undermost unpaired l)undle is the largest of 

 all and towards the upper portion of the petioles the jiaired 

 bundles gradually decrease in size. The uppermost pair, when 

 the upper surface of the petioles is deeply grooved, enters into 



