ARTICLE XII. 



A CONTKIB D T 1 N T THE KNOWLEDGE OF THE FLORA F X II B COAL PERIOD IN T H E 



UNITED STATES. 



is V II OH, AT TO 0. WOO 11, JR., M. D., 

 PROFESSOR OH BOTANY, AUXILIARY MEDICAL FACULTY, UNIVERSITY OF PENNSYLVANIA. 



Bead September 21, 1866. 



The specimens upon which this paper is founded are all of them in the Cabinet of the 

 Academy of Natural Sciences in this city. Much of the memoir is a review of several 

 papers published some years since in the Proceedings of the Academy, and is the result 

 of a careful reconsideration and study of the subject with the light of further specimens 

 and new publications. 



Sigillaria, Brongt. 



S. solene, Wood. Stem costate; ribs strongly convex, approximate, distantly irregu- 

 larly striate, with a well-marked central groove or broad channel; leaf-scars situated in the 

 groove, small, subovate ; vascular scars situated near the smaller end, 3, the central a dot, 

 the lateral linear, arcuate. 



The central portion of the channel between the scars is finely and closely striated like 

 chasing ; at the position of the scars the groove is slightly widened ; the lateral margins 

 of the leaf-scars are not regularly curved, but have a faintly marked angle near the base. 

 The distance between the scars is from five to six times their length. This species is 

 allied to S. rugosa and S. elongata ; it differs from both in the smallness of its leaf-scars 

 and their remoteness one from the other. It also wants the rugosities of rugosa. When 

 decorticated the ribs are very strongly striate. 



S. -solanus, Wood. Proc. A. N. S., vol. xii, 1860, p. 237. 



The type specimen in the Museum of the Academy is very large. 



S. cymatoides, Wood. Stem costate ; ribs very narrow ; furrows distinct, rather broad, 

 marked, as are also the ribs, in the decorticated state, with numerous close striec; scars large, 



