8. 



tudinal imticlino { ILFi-'-s. 6, lo), hut instead of bein,-: 

 radial it i"? nearly paralell to tho inner or nedian border 

 of the se.'Tnent, nmnin.p: from wall I to tlie ventral outer 

 "border of tlie secondary mar.'^inal cell, thus cutting off 

 section II and leaving a tertiary niarr^inal cell (n.c/^' "'■' ". 

 10. 11 ). In eacli of these sections and in tlie tertiary mar- 

 iq-inal cell v/alls are fomed in various planes nearly si- 

 multaneoiTsly as tlie leaf ?:rov/s. In section I tliere is form- 

 ed first a pericline (pi. v;,^Fi". 11 ), at ahout one thdrd 

 of the distance outvmrd from the center of the leaf, cut- 

 ting off thus at tlie inner end a part of the plerome con- 

 trihuted by tliis section to tlie ELxial "bundle of the leaf. 

 Tlien a longitudinal and radial anticline, v^liicli v/e m.ay 

 call the halving anticline, cuts the outer cell into tv;o 

 (h.a.jFigs. 7, 11 ). Meantime the plerom.e of section II is 

 cut off "by a pericline (Fig. 11 ), v/hile the tertiary mar- 

 ginal cell divides "by a transverse ariticline (t.a.j Figs. 

 6. 7) into pji acroscopic and a basiscopic marginal cell. 

 Tliis anticline is the "radial vfall"of Sadebeck, 



The furtlier divisions can best be described by flaking 

 up first the fate of the t\Yo tertiary marginal cells. In 

 eacl^ of these there is formed first an anticline (IIIjFi-. 

 11 ) nearly paralell to v/all I and tovrrd tl^.e dorsal side of 

 the marginal cell; then a similar wall is formed towrd tlie 

 ventral side paralell to wall II (IV Fir;e. fi. If-). Tliere 



