70 PHOENICOPSIS [CH. 



in the case of detached leaves which it is often impossible to 

 determine even generically. The characters usually employed for 

 the separation of different forms are conveniently shown in a table 

 published by Krasser^. There is no information available as to 

 the epidermal structure of the various types of Phoenicopsis leaves, 

 nor have we any data with regard to the reproductive organs. The 

 genus is generally included in the Ginkgoales: the dwarf-shoots 

 agree closely with those of Czelcanowskia which, in the structure 

 of the epidermis and in the bifurcation of the leaves, resembles 

 Ginkgo and Baiera. The precise position of Phoenicopsis cannot 

 be regarded as settled. The only evidence with regard to ana- 

 tomical structure is that furnished by Solms-Laubach^ who 

 described petrified leaves from Jurassic rocks in Franz Josef 

 Land which are probably examples of Phoenicopsis ; but, assuming 

 that they belong to this genus, the anatomical data are insufficient 

 to determine the position of the genus within the Gymnosperms. 

 Incomplete and detached leaves agreeing in their venation and in 

 the form of the lamina with those of Phoenicopsis cannot as a 

 rule be distinguished from leaves of Podozamites, Feildenia, or 

 even from narrow forms of Cordaites. The Jurassic specimens 

 from North Germany on which Salfeld^ founded the genus Phyl- 

 lotenia should probably be assigned to Phoenicopsis. Solms- 

 Laubach refrained from assigning the imperfect Franz Josef 

 Land leaves to Phoenicopsis because no dwarf-shoots were found ; 

 he employed the non-committal generic name Desmiophyllum, a 

 designation that might with advantage be more frequently used 

 for specimens which cannot be proved to belong to Phoenicopsis, 

 Podozamites or other genera with similar leaves. 



Desmiophyllum. Lesquereux established the genus Desmio- 

 phyllum* for some narrow sublinear leaves from the Coal Measures 

 of Pennsylvania similar to those of Poacordaites and attached to 

 an imperfectly preserved axis either singly or in small groups. 

 The type-species D. gracile is probably a species of Cordaites : the 

 name Desmiophyllum never came into general use until its revival 

 by Solms-Laubach in 1904 as a convenient term to apply to linear 



1 Krasser (05) p. 612. 



2 Solms-Laubach (04) Pis. i., n. ^ Salfeld (09) B. p. 26, PI. iv. fig. 3. 

 « Lesquereux (78) p. 322; (80) A. p. 556, PI. 82, fig. 1. 



