526 PTERIDOSPERMS, ETC. [CH, 



primary pinnae of Pecopteroid and Sphenopteroid fronds 

 (e.g. Dactylotheca plumosa, fig. 293)^. 



Modified pinnules, similar in their reduced and deeply 

 dissected lamina to those represented in fig. 293, are frequently 

 found at the base of the primary pinnae of Palaeozoic species of 

 Sphenopteris and other genera of Pteridosperms or ferns, including 

 members of the Coenopterideae. Potoni^^ gives a list of various 

 types of Aphlebiae in his paper on these organs. A striking 

 case has recently been described by Zeiller in a French Upper 

 Carboniferous species, Sphenopteris Maiheti^. It would seem 

 that the larger examples of Aphlebiae are more frequently 

 associated with the compound leaves of Pteridosperms than 

 with those of Ferns*. 



As examples of the larger types of Aphlebiae reference may 

 be made to Aphlehia crispa (Gutb.)*, which reaches a length of 

 nearly 60 cm. and has the form of a more or less triangular 

 pinnate leaf divided into decurrent deeply lobed segments, to 

 a similar species represented by A. Germari (= Schizopteris 

 lactuca Germ.)® which simulates the leaves of endive {Gichorium 

 endivia L.), and to some large forms figured by Grand'Eury^ as 

 species of Schizopteris. 



Aphlebiae such as that figured by Kidston^ as Rhacophyllum 

 crispum, with narrow ultimate segments, might easily be 

 mistaken for the impressions of an alga. 



The term Aphlebia may be applied also to the Cyclopteroid 

 pinnules on the petioles of some species of Neuropte'ris, Odonto- 

 pteris and Archaeopteris. GoebeP has referred to the application 

 by Potoni^ and other authors of the term Aphlebioid to the 

 pinnules which serve as bud-protecting organs in recent fronds 

 of Gleichenia (fig. 226, p. 290); he expresses the opinion that it 

 is superfluous and misleading to make use of a special desig- 

 nation for structures which are undoubtedly modified pinnules. 

 In the case of fossils it is, however, convenient to employ 

 the term Aphlebia as a descriptive name for modified pinnules 



1 Page 406. 2 Potoni6 (03) p. 162. 3 ZeiUer (06) Pis. vi. vii. 



* Arber (06). » Renault and Zeiller (88) A. ; Zeiller (88) A. PI. m. 



" Renault and Zeiller (88) A. PI. xxiv. ' Grand'Eury (90) A. PI. xix 



8 Kidston (91) PI. XXXV. » Goebel (05) p. 318. 



