MATONINEAE 



569 



A 



T 

 J 



'i'he process thus described may then be repeated in that central strand : 

 it becomes cylindrical, forming the second vascular ring, which is still 

 connected at the nodes with the foliar 

 system (Fig. 319 u), and a fresh central 

 strand originates internally from it : 

 this in its turn becomes cylindrical 

 in the most advanced types, but still 

 maintains its connection with the 

 middle and outer rings in the neigh- 

 bourhood of the nodes. The whole 

 development is in fact an extreme 

 type of the progression described by 

 Gwynne-Vaughan in other solenostelic 

 Ferns. 1 He showed how an internal 

 vascular system may arise by progres- 

 sive elaboration from a local thickening 

 of the margin of the leaf-gap of the 

 original solenostele. In Matonia this 

 development is the same, but it may 

 be twice repeated. 



It is indicated by the palaeophy- 

 tological evidence that while the 

 Matonia-type is an ancient one it is 

 not among the earliest. This a*ccords 

 with the soral and anatomical char- 

 acters ; for the sorus, though of the 

 Gleicheniaceous type, and still form- 

 ing its sporangia simultaneously as in 

 other Simplices, shows an advanced 

 feature in the indusium, as also in 

 the lateral dehiscence, and small 

 spore-output. Anatomically the indi- 

 cations are of the same nature : 



FIG. 319. 



,, . . . , ..-, . Matonia pectiiiata, drawing from \v;i.\ models of 



Matonia accords With G. pectlliata in the stelar system. ^= from a young stem showing 



, , . node. A' = from an older stum, showing node seen 



the SOlenOStellC StrUCtUJe, but Carries from behind. C=still older node, .seen from in 



that line of elaboration much further. JSLo X * 5 ' ^ 



Finally, in the rhizomic habit and in 



the branching of the leaf there appears to be further similarity : there is 



indeed sufficient reason to regard the Matonineae as a family related to 



the Gleicheniaceae, but advanced in several respects beyond that type, 



in directions which are represented more fully in other series of Ferns. 



1 Ann. of not., xvii., p. 703. 



