554 



CYCADOPHYTAN FRONDS 



[CH. 



with the axis. There is a close resemblance between this species 

 and Sphenozamites Rogersianus Font. 1 : in the American type the 

 fronds must have been 1 met. long; the leaflets, 19 x 9 cm., 

 are elliptical, broadest near the apex and attached by the middle 

 of the rounded base. Between the divergent and forked veins 

 there is a fine granulation probably due to the presence of papillae. 

 Pterophyllum Bronni and P. Rogersianum might be placed in 

 Schimper's genus Macropterygium 2 , though another Raibl species, 

 originally described by Schenk as Pterophyllum giganteum 3 and 

 referred by Schimper to Macropterygium, has much longer and 

 relatively narrow pinnae and agrees more closely with Ptero- 

 phyllum as the genus is usually defined. In order to emphasise 

 the distinctive features of Pterophyllum Bronni and Fontaine's 

 Virginian species they may con- 

 veniently be spoken of as Ptero- 

 phyllum (Macropterygium) Bronni 

 and Pterophyllum (Macropterygium) 

 Rogersianum. 



Pterophyllum Braunianum Goeppert. 

 In this Rhaetic species 4 (fig. 613) 

 the narrow linear pinnae, contiguous 

 or more or less distant, are 1 2 mm. 

 broad and may exceed 5 cm. in length 

 though they are usually shorter; 

 they are attached more or less at 

 right-angles to the sides of a trans- 

 versely wrinkled rachis. The base 

 of the lamina is broadened and the 



veins are parallel, simple or forked. FIG. 613. Pterophyllum Braunia. 

 The epidermal cells have sinuous 

 walls. 



a 



. (A, nat. size; B, enlarged; 

 after Schenk. ) 



Pterophyllum Tietzei Schenk. 



A Rhaetic species founded 5 on specimens from Persia and 

 described also by Zeiller 6 from Tonkin represented by fronds 



1 Fontaine (83) B. p. 80, Pis XLIII. v. 2 Schimper (72) A. pp. 121, 132. 



3 Schenk (67) PI. n. * Goeppert (44); Schenk (67) A. p. 164, PI. xxxvm. 



5 Schenk (87) B. p. 6, Pis. vi., ix. 



6 Zeiller (03) B. p. 189, PI. XLVII. fig. 1. 



