MARATTIACEAE 



[CH. 



was also described by Christ and Giesenhagen for Archangiopteris {Flora, 

 Ixxxvi, p. 72, Fig. I. 7, 1899). It has been shown for Ferns at large that simple 

 hairs are primitive and scales an indication of advance (Vol. I, Chapter xi). 

 Thus Christenseiiia, Daiiaea, Protoinarattia, and Archangiopteris stand out 

 from the rest in respect of this minor feature as relatively advanced types : 

 the three first named all have synangial sori, extended superficially far from 

 the margin. 



Fig- 39'- Vertical section of the stem of a young plant of 

 Angiopteris evecta. h = the youngest leaves still quite covered 

 up by the stipules (nd) ; j/ = stalk of an unfolded leaf, with its 

 stipules; w = the leaf-scars where leaves have fallen away; 

 c, f = commissures of the stipules in longitudinal section; 

 w, w = roots. (Natural size.) (After Sachs.) 



The roots originate internally beneath the growing point of the stem 

 (Fig. 391). In small plants there may be one root to each leaf, but in strong- 

 growing plants the roots are more numerous. They take a course obliquely 

 downwards through the tissue of the stock, finally issuing as robust roots 

 which branch monopodially. 



The sori in this Family are always intra-marginal on the lower surface of 

 the leaf: they are distinct from one another, seated each upon a vein. As 



