440 CONIFERALES INCERTAE SEDIS [CH. 



characterised by its deeply split cone-scales. Schenk 1 subsequently 

 substituted the name S. Braunii and included under that designa- 

 tion Braun's Isoetites pumilus, a species founded on a foliage-shoot , 

 also some other similar vegetative branches believed to belong- 

 to the plant which bore the cones. As here used, the term 

 Schizolepis is restricted to cones and cone-scales since there is no 

 definite evidence as to the nature of the foliage-shoots connected 

 with the strobili. Schizolepis cannot be referred on any satis- 

 factory grounds to a definite position among the Coniferales: it is 

 possibly an extinct type allied to recent Abietineae, but until 

 more is known with regard to the morphology of the cone-scales 

 the systematic position must be left an open question. The genus 

 is represented by strobili from Rhaetic beds in Franconia, Scania, 

 and Poland; detached scales from Middle Jurassic floras are also 

 included in Schizolepis (fig. 808), arid Nathorst has described 

 incomplete strobili from Upper Jurassic or Wealden strata in 

 Spitzbergen. Attention has been called to a resemblance between 

 Schizolepis scales and the fertile leaves of Tmesipteris 2 , but there 

 is no reason for regarding this as indicative of relationship. More 

 than one author has compared the bilobed cone-scales of Schizolepis 

 with the 3 5-lobed scales of Voltzia and Cheirolepis though this 

 comparison rests on a feature which in itself is no proof of affinity. 

 A comparison may also be suggested with the reflexed cone-scales 

 of Picea Brewer iana. 



Schizolepis Braunii Schenk. 



It has already been painted out that under this name Schenk 3 

 included both cones and vegetative shoots though he recognised 

 the lack of any decisive evidence of common parentage. While 

 agreeing with Nathorst that the association with Schizolepis 

 strobili of similar vegetative shoots both in Germany and Sweden 

 may be more than accidental, in the present state of our knowledge 

 it is preferable to refer the leaves and branches to Pityophyllum or 

 Pityocladus. In the younger strobili the bilobed scales are more 

 or less pressed against the axis and in older examples they are 

 more spreading : each scale has two lanceolate lobes and is attached 



1 Schenk (67) A. p. 179. 



2 Nathorst (97) p. 61. 



3 Schenk (67) A. p. 179, PI. XLIV.; Schimper and Schenk (90) A. p. 306. 



