1^2 S- MATSUDA. 



vnsciilar hiinrlles are in many cnses arranîred as in the stem ; that is, 

 in tlie cross section of the ]>eti()le, they ]^reNent a circiilnr arrangement 

 enclosino- the pith in the centre (?J. 11, Fi,i>-. ß). But in the petiole 

 of llh'chim, J)n'm)i!^, Trochodcndwn, Kadiura, and SchizaNdra, the iihro- 

 vascnlar linndles have a semi-circnlar arrano-ement with the concav^ity 

 turned to the npper side of the petiole (PI. IIT, Fia'. 7). The 

 sclerenchvniatf^ns sheatli of the Inindles is often wanting', as in the 

 petiole of lUicium, Dn'imj.'^, and Scliizandra. Troeliodfudwn has the 

 sheath consistino- of nnho^nified fihres, while all the other o^enera have 

 well developed sclerenchymatons sheatlis (PI. TI, Fii;'. ()). The fihres 

 forming- these sheaths remain nnlignified at the hasal pt^rtion of tl^e 

 petiole in all cases, except in the ])etiole of Lin'odpndron. where a few 

 fihres are found lio-niiied. Wliether this local non-lignification of the 

 iihres has some pli3^siological meaning or not still remains undecided. 

 In .T/rvf///o//>o' dia]ih7'agms are found in the pith-])ortion of the petiole 

 as ill that of the stem. 



Blade. 



The general structure of the hlade does not deviate from the 

 dicotyledonous tvpe. 'i'lie up])er portion of it is made up of palisade- 

 parenchvma, whi<h consists of vertically elongated cells varying in 

 diffeient species from one to several layers. Wliere these cells lie 

 di recti v over the main rihs. their height is generally diminished and 

 their f)rm hecomes almost round. The lower portion of the hlade is 

 generally made up of loose ]>arenchyma ; hut in those ])arts lying 

 directiv under the main I'ihs there is found a more compact ])ai'en- 

 chvmatous tissue. Tn some genera, namely, Jlliciinn, Trocliodoidroti, 

 ]\[cu}Noli((. and Michelin, the l)lade has a well developed cuticle. In 

 Sclri:(Uidreœ the cuticle of the midrih — especially that of the lower 

 surface— forms fine ridges running longitudinally (PI. TI, Fig. 'î). 



