XXIIl] 



PSARONIUS 



419 



different degrees of looping of other bands represent stages 

 in the giving off of leaf-traces which eventually pass out 

 as V-shaped meristeles. Beyond the leaf-traces and scleren- 

 chymatous bands the section consists of transverse sections of 

 adventitious roots. 



The surface-features of Psaronius infarctus are probably 

 represented, as Zeiller points out, by the cast described by 

 Lesquereux as Caulopteris peltigera (fig. 298, A). 



Fig. 297. Pecopteris Sterzeli : a, pinnule. (After Eenault and Zeiller. yV iiat- 

 size.) 



The Psaronius shown in fig. 297 is one of the few examples 

 illustrating the connexion between fronds and stem. The leaf 

 (Pecopteris Sterzeli Zeill. and Ren.^) is quadripinnate and is 

 described as reaching a length of at least 3 metres ; the 

 ultimate segments are entire or lobed. The stem is charac- 

 terised by elliptical scars, 6 — 8 cm. x 3'.5 — 4 cm., with leaf- 

 traces like those in Caulopteris peltigera. The fronds of 

 Pecopteris Pluckeneti, a Pteridosperm, bear a very close 



1 Benault and Zeiller (88) A. Pla. v.— viii. 



