564 FILICALES 



EMBRYOLOGY. 



The development of the embryo appears to follow the type usual for 

 Leptosporangiate Ferns, but the details are not adequately known. 1 



The Palaeophytological evidence coupled with the anatomical and soral 

 characters indicates for the Gleicheniaceae a position among relatively 

 primitive Ferns. The comparative examination of the living species leads 

 to the recognition of G. ftabellata as a central type. This is not so much 

 suggested by the external form, as by the sorus, the stelar structure, the 

 relatively simple insertion of the leaf-trace, and the non-involuted strand 

 of the petiole. This species also shows the largest spore-output per 

 sporangium observed in the family. There has probably been a line of 

 diminution of the individual pinnules to produce the condition seen in 

 Eughichenia, together with a reduction in number of the sporangia in 

 the sorus, leading to a type of monangial sorus similar to that of the 

 Schizaeaceae. A line of probable advance has been to such forms as 

 G. pectiuata and dichotoma ; for not only do these species show interpo- 

 lation of extra sporangia in the sorus, together with smaller sporangia 

 and diminished output per sporangium, but also they are anatomically 

 more complex. This is specially shown by the large nodal pockets of 

 G. dichotoma^ and ultimately by the continuous solenostely seen in G. 

 pectinata. In both respects these species indicate changes from the central 

 type in the direction of Cyatheaceous characters. 



MATONINEAK. 



This family 2 is represented by only two species of living Ferns, Alatonia 

 pectinata and M. sarmentosa, both of limited distribution in the Malayan 

 region. But Ferns referred to this affinity on the characters of leaf and 

 fructification played a prominent part in the vegetation of the Secondary 

 Rocks, and have been traced back as far as the Rhaetic period : this 

 fact accords with the unmistakable analogies which they show to the 

 Gleicheniaceae. 



The two living species differ in habit : M. pectinata is a stout, ground- 

 growing species, with elongated creeping rhizome, covered with filamentous 

 hairs, and branching in an apparently dichotomous manner. It bears 

 solitary leaves at considerable distances apart on its upper surface. 

 These grow to a height of 6 to 8 feet, and have a very characteristic pedate 

 construction of the lamina, which is referable to a dichotomous system 

 of branching (Fig. 315): even the ''middle lobe," which often appears 



1 Rawenhoff, Arch, Neerl., T. xxiv., p. 223. 



2 The chief sources of information have been Natur. rjliui-..,-ni\i>n., \. 4., p. 343; 

 Seward, Phil. Trans., vol. 191, p. 171 ; Tnn-lry and l.ulham, Ann. of Bot., vol. 

 xix., p. 475, and my own ^Indies, iv., p. 44. 



