CHAPTER XXXIII. 
MARATTIACEAE. 
Tuis family is represented by five genera of living homosporous Ferns, 
viz. Angtopterts, Archangiopteris, Marattia, Danaea, and Kaulfussta. 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 Axgtopteris, 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 (eg. D.. simplicifolta): -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. alata, 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 He/min- 
thostachys the primitive shoot with its massive stock has given way to a 
more elongated but creeping rhizome. (See Chapter XVI.) 
