XLV] PA6I0PHYLLUM 275 



ently be reserved for vegetative branches of Conifers (fig. 744) 

 possessing foliage like that of Araucaria excelsa and allied species, 

 which in the absence of cones cannot safely be referred to Elatides 

 or other genera based, in part at least, on strobilar characters. 

 Pagiofliyllum is essentially an artificial genus : as Solms-Laubach 

 says, 'it is only in accordance with old custom to distinguish the 

 UUmanniae of the Zechstein from Pagiophyllum^,' and it is equally 

 difiicult to draw any clearly defined line between this genus and 

 some forms included by authors in Brachyphyllum. A Triassic 

 species from Raibl originally referred to Yoltzia heterophylla^ 

 afterwards named V. Foettleri by Stur', Pagiophyllum Sandbergi 

 by Schenk* and figured by Schiitze^ as P. Foettleri, has the habit 

 of a Brachyphyllum. This is one of many examples of sterile 

 shoots illustrating the arbitrary use of generic names for coni- 

 ferous remains which afford no definite evidence of their systematic 

 position. The Araucarian habit is in itself of little value as 

 evidence of afiinity, but the abundance of petrified wood with 

 Araucarian features (Dadoxylon) in strata yielding Pagiophyllum 

 shoots suggests an Araucarian alliance, and the fact that some 

 Pagiophyllum shoots bear Elatides cones affording indications of 

 Araucarian characters points in the same direction. It cannot 

 be assumed that all Pagiophyllum shoots bore similar cones, and 

 it is mainly on this account that the employment of Pagiophyllum 

 as a provisional designation is recommended. 



Pagiophyllum is widely distributed in Jurassic strata and 

 extends into Cretaceous and Tertiary rocks : it occurs also in 

 pre-Jurassic floras and has recently been described by Zeiller* 

 from the Permian of France. It should be recognised that this 

 extended use of the name is not in accordance with general practice, 

 but it is' adopted on the ground that, as in recent Conifers so in the 

 case of extinct types, similarity in the habit of vegetative branches 

 does not necessarily imply close relationship as regards the more 

 important characters of the reproductive shoots. 



1 Solms-Laubach (91) A. p. 77. 



2 Bronn (58) p. 135, PI. viu. 



3 Stur (68) p. 104. 



« Sohimper and Schenk (90) A. pp. 276, 290. 

 6 Sohiitze (01) PI. VI. fig. 1. 

 « Zeffler (06) B. p. 219, PI. Li. 



18—2 



