CHAPTER XXXIII 



MARATTIACEAE. 



THIS family is represented by five genera of living homosporous Ferns, 

 viz. Angiopteris, Archangiopteris, Marattia, Danaea, and Kaulfussia. The 

 characters of all the five genera are now well known, so that they form 

 a sound basis for comparison with the fossils. A number of these, dating 

 back to the Palaeozoic period, show strong similarity to the modern 

 forms, both as regards anatomy and the characters of the sorus. Their 

 existence indicates that the Marattiaceous type has been a very ancient 

 one. The natural course will be first to consider the living Marattiaceae : 

 we shall then proceed to compare with them their fossil correlatives. 



EXTERNAL CHARACTERS. 



The erect stock in Angiopteris, Marattia, and Archangiopteris is 

 relatively short, massive, and unbranched : it is of the radial type, and 

 is entirely covered by the persistent bases of the crowded leaves 

 (Fig. 274). It continues directly the radial symmetry initiated in the 

 embryo, which is probably a primitive condition. Some species of 

 Danaea have also an erect radial shoot (e.g. D. simplicifolia} : others 

 show at first an erect position and radial construction, but it passes 

 over gradually to an oblique position, with distichous arrangement of 

 the leaves (D. a/a fa, Fig. 275). Kaulfussia, on the other hand, is 

 strongly dorsiventral, its rhizome showing distinct internodes, and being 

 horizontal, while the leaves alternate obliquely on its upper surface 

 (Fig. 276). It seems a natural interpretation of the facts to hold that 

 in the last named Ferns the primitive radial and erect type of the shoot 

 has been relinquished in favour of the derivative creeping habit, which 

 goes along with its diminished bulk and greater elongation: in fact, the 

 case is similar to that seen in the Ophioglossaceae, where also in Hclniin- 

 thostachys the primitive shoot with its massive stock has given way to a 

 more elongated but creeping rhizome. (See Chapter XVI.) 



