PENNSYLVANIA TREE FERN COMPRESSIONS 



Langford (1958, fig. 

 241) figured a specimen having 

 a row of leaf scars from the 

 Francis Creek Shale Member at 

 Wilmington (text fig. 3, B) 

 that had been figured before 

 by Noe (1925, pi. 45, fig. 5) 

 and Janssen (1957, fig. 88). 

 Langford designated this spec- 

 imen (UP 423 = UC 40001) Mega- 

 phyton braidwoodense , which is 

 a nomen nudum. It is not 

 clear whether the specimen 

 belongs to Megaphyton or 

 Caulopteris . 



Text fig. 3 - Species of Megaphyton 

 and Artisophyton from Illinois. 

 A - M. protuberans; B - Specimen 

 UP 423 = UC 40001 from the Francis 

 Creek Shale; C - A. insignis; 

 D - A . mclayi . 



1 cm 



1 cm 



Artisophyton gen. nov. 



Diagnosis . — Stem of tree fern (compression or impression); leaf 

 scars in two vertical rows on opposite sides of the stem; leaf scars 

 round or rounded rectangular; leaf scars often in continuous rows; outer 

 trace of vascular bundle closed, with deep indentation on the lower 

 (abaxial) side; some leaf scars may show a final stage in which the 

 outer trace is divided into two separate closed traces; inner trace 

 developed from a straight line into two S-shaped traces (text fig. 4). 



Derivation of name . — Artisophyton is a combination of the 

 surname of E. T. Artis, who recognized in 1825 that Megaphyton had much 

 in common with living tropical tree ferns, and the Greek word for plant 

 (phyton) . 



Type species : 

 1834) comb. nov. 



Artisophyton approximation (Lindley and Hutton, 



Basionym of type species ; Megaphyton approximatum Lindley, John, 

 and William Hutton, 1833-35, Fossil flora of Great Britain or figures 



