156 



THE MARATTIALES 



the Statement (Campbell 3, page 14) that in Marattia douglasii the primary root 

 is tetrarch I have found to be based upon a mistake, the root which was so de- 

 scribed not being the primary root, but evidently one of the later ones. I have 



occasionally found very strong plant- 

 lets in Dancea, where the primary 

 root was triarch, as it sometimes is 

 in Botrychium, and very commonly is 

 in Helminthostachys; but such spe- 

 cimens are not common. The root 

 bundle is bounded by a conspicuous 

 endodermis, whose cells show very 

 plainly the characteristic radially 

 thickened bands (figs. 143, en; 144). 

 The endodermis gradually loses its 

 definite appearance at the junction 

 of the root and leaf bundles, and I 

 have not been able to recognize it 

 above the level of the base of the 

 cotyledon, although it is not at all 

 impossible that with proper staining 

 it might be traced further up. 



THE SECOND LEAF, 



The second leaf begins to develop while the cotyledon is still small, and by the 

 time the latter ruptures the overlying prothallium tissue the second leaf is clearly 

 evident as a flattened cone, closely resembling the early stage 

 of the cotyledon. In Kaulfussia the second leaf arises quite 

 close to the cotyledon and on the same side of the stem apex, 

 ^ so that the dorsiventral character of the stem is already indi- 



V^ /TTTTTTTa cated at this early stage of development. In the other genera 

 the second leaf arises nearh- opposite the cotyledon, but not 



Fig. 140. 



A. Stem apex of a young sporophyte of Dana-ajamaicensis, showing single apical cell. XlSo. 



B. Second leaf from same. 



C. D. Sections of primary roots, showing apical meristem. Xl8o. 



H ' A 



Fig. 139. 



A. Transverse section of a young sporophyte of Marattia douglasii. 



w, stem apex. X150. 



B. The stem apex. X360. 



exactly so, and the subsequent leaves form a spiral, and for a time at least, except 

 in Kaulfussia, the anatomy of the shoot is radial. This radial arrangement is 

 retained permanently in Marattia and Angiopteris and also in some species of 



