136 



s. MATSÜDA. 



the lenf-bhide. and some of the cells constituting it become sclerotic 

 as this region is ajiproached, and, together with the sclerenchymatoiis 

 fibres that abound there, form a very strong margin to the blade. 

 The blade of JSIdijuoJia (jniHdijIora is also itself very thick, the palisade- 

 ])arenchyma consisting of several layers of cells, but in MaijuoJui 

 mlicifoh'a, which has very thin leaves, there is only a single layer of 

 cells constituting the palisade parenchyma. Although there are the few 

 just noticed peculiarities to be detected in certain species, the gener«al 

 structure of the blade is similar in the three genera of ]\fa<inolie(v. 

 The fibro- vascular bundles are circularly arranged in the midrib, as 

 they :dso are in the petiole. Resin-sacs are found in the leaf-blades 

 of all the s])ecies examined. The (K'currence of stone-cells is also 

 very general. MiKjHolid piniiiJa contains somewhat el(^ngated scleren- 

 chymatous cells in the hy])odermal region of the lower side of the 

 midrib. Red ])atclies ai'e often met with in the n.esophyll of some 

 species of MtKiHoli/i, c |/., il/, ohovata, M. cou^]yieu(i, and M. coiisjricua 

 ^'ar. jivrpinrscrns. These were proved to be tannin. 



Boot. —The general structure of the older root does not nnich 

 deviate from that of the stem. Resin-sacs are ])resent without 

 exception in the outer cortex. This region also contains a number of 

 scleroblasts in some species, while it is destitute of them in others, 

 'I'he sclerenchvmatous fibres are generally developed at the external 

 limit of the ])hl<x'm. Pith is absent, and its place is occu])ied by a 

 group of elongated woody fibres. In the young root the number of 

 xylem-plates is very variable. Thus in Lin'o<lr)i<Jron their arraiigement 

 is diarch or triarch, but mostly the former. In MicJielia it is triarch or 

 tetrarch (PI. V, Fig. 3i, A). In Miij)u^Un diarch, triarch, and tetrarch 

 arrangements are each commc^n ; but in one species, namely, ^hufiinVut 

 fjraudißoni, the arrangement varies from tlie tetrarch to the heptarch. 

 General l\', \vlu;n the root becomes a little oldei" the xylem-plates which 



