238 FLOEA OF LOWER COAL MEASURES OF MISSOURL 



paleobotanists are now agreed in treating the forms previously distributed 

 in the above sections as a single group or subgenus of Sigillarise. Thus 

 they were made by the late C. E. Weiss the subject of an elaborate and 

 admirable discussion, since completed with conscientious efficiency and 

 delicacy by Dr. Sterzel, under the title Die Subsigillarien} This term for 

 the group was adopted by Potonie,- who for the Rhytidolepis, Tesselkda, and 

 Favularia sections (or Bhjtidolepis in the broadest sense) employs the group 

 name EtisigiUarim. M. Grand 'Eury, who at first ranged the species grouped 

 about SigiUaria camptotcenia in a genus which he named Pseudosigillaria and 

 placed in the Lepidodendrem,^ has since restored them to the Sigillarice 

 under the comprehensive group term SigillaricB-camptotcenicB,'^ which cum- 

 bersome and inconvenient term he adopts, in the singular, for generic use, 

 employing for the type described by Wood the name Sigillaria-camptotmnia 

 ■ monostigma Lesq. Potoni^ I'igl^tly points out the propriety of retaining for 

 Wood's genus, amended, the original name Asolanus. 



It is interesting to note that Nathorst^ particularly remarks on the 

 characters in common between SigiUaria rimosa and Bothrodendron {Cyclo- 

 stigma) Kiltorkense Haught. sp., which he regards as probably related, while 

 Weiss'^ includes in the SuhsigillaricB both the Cydostigma (Bothrodendron?) 

 Kiltorkense, and the genus Bothrodendron, the latter being enrolled as a sub- 

 genus of SigillariecB. To the writer the group of species centered about 

 S. camptotcenia Wood, S. corrugata Lx., or Bothrodendron, seems to stand on 

 the side of the SigiUariece that is nearest the Lepidodendre(B, betAveen which 

 and the SigiUariece it helps to bridge the gap. 



SigiUaria camptotcenia is distinguished from other species in the group 

 SuhsigiUarice by the concave lateral' margins of the distant leaf scars, the 

 attenuated lateral angles, the very long, linear, crescentic, lateral cicatricules, 

 extending nearly the whole height of the scar and apparently forming an 

 oval or obovate ring, and especially by the ropy, meshed cortical striatious 

 extending from each leaf scar to the four scars nearest thereto. 



Localities. — Pitcher's coal mine, U. S. Nat. Mus., 6064; Gilkersou's 

 Ford, U. S. Nat. Mus., 6063. 



' Die Sigillarieu der Preussischcn Steinkohlen und Rothliegendengebiete, vol. ii ; Die Gruppe der 

 Subsigillarien : Abh. d. k. Pr. geol. Landesaust., N. F., Hft. 2, Berlin, 1893, pp. xvi, 255. Atlas, pi. i-s.xviii. 

 = Loc. cit., p. 24. ■' Op. cit., p. 64. 



^Fl. carb. Loire, 1877, p. 142. " Op. cit., p. 60. 



*G6ol. at pal. bassin houill. Card, 1890, p. 260. 



