IX 



MA RA TTIA CEyE—ISOE TA CE^ 



269 



comes to the same conclusion as Holle, although in an earlier 

 paper ^ he attributes a single apical cell to the stem of Angi- 

 opteris. The stem in both genera becomes very massive, but 

 its surface is completely covered by the persistent stipules. 

 The arrangement of the bundles is like that of Ophioglossum, 

 and they form a hollow cylinder with distinct meshes corre- 

 sponding to the position of the leaves. The bundles are, 



Fig. 141. — Marattia Dati£-lasn (Baker). A, Cross-section of the ultimate rachis of a fully-developed 

 leaf, X 26 ; B, part of the vascular bundle of the same, X 200 ; C, coUenchj'ma from the cortex 

 of the same, Xiso; D, cross-section of the lamina of the cotyledon, X200; .ly, xylem. 



according to Holle,"' concentric, but the phloem more strongh' 

 developed upon the outer side. 



The thick petioles of the full-grown leaves are traversed b}^ 

 very numerous vascular bundles, which at the base give off 

 branches that supply the thick stipules within which they 

 branch and anastomose to form a network. These bundles in 

 A^igiopteris are arranged in several circles, or according to 

 De Vriese and Harting,^ the central ones form a spiral. In 

 the rachis of the last divisions of the leaves, however, both of 



^ Bower (2), p. 579. 



- Holle (2), p. 217. 



^ De Vriese (i). 



