MARATTIACEAE 



[CH. 



been observed. Though the feature is variable in both of them, it may be 

 held as confirming their primitive position, which is itself based upon many 

 other lines of comparison, as well as upon the positive data of Palaeontology 

 as far as the Marattiaceae are concerned. 



The body of the embryo of the Marattiaceae, which has already been 

 discussed in Vol. I, Chaptea- XV, presents features similar in the main to those 

 of Botrychiuin and Ophioglossiim. The segmentations are less regular and 

 definite than those of the Leptosporangiate Ferns. The epibasal hemisphere 

 gives rise to axis and leaf (Fig. 415). Campbell recognises a definite prismatic 

 initial cell at the apex of the axis oi Marattia, but no single apical cell could be 



Fig. 414. Section tlirough a prothallus of Fig. 415. Marat tia Douglasii. A — 



Angiopteris (after Land). Above is an longitudinal section of a young 



antheridium, deeply sunk: below is a fer- embryo( x 225): (^,(5 = thebasahvall: 



tilisedarchegonium, with an embryo, showing the arrow points to the neck of the 



a well-developed suspensor. ( x 200.) archegonium. i? = a similar section 



of an older embryo, showing its 

 positionintheprothallus: j'/'=steni : 

 /';-= prothallus: ar=neck of the 

 archegonium. (x 72.) (AfterCamp- 

 bell.) 



made out in the cotyledon [I.e. p. 282), From the hypobasal hemisphere the 

 root is formed with at first a single initial of irregular form, but there is no 

 distinct haustorial organ which could properly be distinguished as a foot. 

 These features all point directly to the Ophioglossaceae in which also the 

 segmentation is less definite than in other Ferns. The emergence of the shoot 

 through the upper surface of the prothallus is constant for the family so far 

 as described, and it is in strong antithesis to the prone embryology of all 

 Leptosporangiate Ferns. Even in Macroglossum it is the same: but in this 

 genus the oblique position of the embryo suggests a possible step from the 

 erect embryology of the Eusporangiatae, towards that prone embryology so 



