xx] 



HABIT 



lOI 



{Bot. Gaz. li, p. 8i. 191 1) and by West {Ann. of Bot. xxxi, p. 361) 



that the stems and roots of the embryos may segment from a single initial 



cell : but this is only a temporary state. 



The stem and root of the adult show a 



bulky type of meristem not referable to 



a single initial. Schwendener {Sits. K. 



Preuss. Akad. 1882) demonstrated this 



for the root, where he found four equal 



initials. A similar structure though less 



regular has been found at the stem-apex 



of Angiopteris and Marattia (Fig. 395). 



But the most convincing evidence of the 



robust structure of the vegetative system 



lies in the massive wings of the leaf-blade, 



which do not show segmentation of a 



single marginal series of cells, as in all 



Leptosporangiate Ferns, but a meristem referable possibly to two rows of 



initials (Fig. 396). All this harmonises with the eusporangiate state of these 



plants and demonstrates the relatively bulky construction of their whole 



sporophyte. 



Fig- 395- .-^=apex of stem of Angiopteris 

 evecla, seen from above. Apparently there 

 are four initials x , x , x , x . ( x 83.) 



Fig. 396. Vertical sections of the massive wings of the leaves of Angiopteris (A, left), 

 and of Todea (B, right), showing segmentation of a complex type. 



Anatomy 

 The Marattiaceae are sappy Ferns, characterised by an absence of 

 sclerenchyma, while their tissues are traversed by lysigenous mucilage- 

 canals. Tannin cells also are widely distributed, either isolated or in groups, 

 and they are present even in the hairs and scales (West, A/i7i. of Bot. 191 5, 

 p. 409). The vascular system of these Ferns is unusually complicated: in 

 some of them it is undoubtedly the most complex of all living Peridophyta. 

 The complication consists in the extreme sub-division of the vascular tracts 

 both of axis and leaf, the strands being disposed in concentric circles, as 

 though resulting from the disintegration of a polycyclic system. There is 



