SI GILL ARIA AND MAZOCARPON 



27 



Sigillariostro'bus does, is best indicated 

 by reference to the few important 

 papers which describe the structure of 

 peduncle steles within petrified stems of 

 Sigillaria. 



. PEDUNCULAR STELES OF 

 8IGILLARIA AND 

 MAZOCARPON 



In 1926 Hagene described a section 

 of a ribbed sigillarian stem from the 

 paleobotanical collections of the Uni- 

 versity of Lille. This specimen appar- 

 ently had been collected and prepared 

 by Hemingway in England. The collec- 

 tion locality was given as *'Colne, Lan- 

 cashire," from the horizon of the Hali- 

 fax Hard Bed coal,^ and Hemingway 

 had labeled it '^Sigillaria elegans". This 

 stem is unique in that it is one member 

 of the Favularian section in which the 

 rather large stele does not possess any 

 secondary wood, and further, in that a 

 large number of small steles, some of 

 which are solid and others medullated, 

 surround the main central cylinder. 

 Numerous leaf traces, single and bar-like 

 near the stele but double in the inner 

 cortex, are also present. Characteristic 

 sigillarian leaves with corresponding 

 double Avascular strands are also asso- 

 ciated in the same section. The pedunc- 

 ular steles are of chief interest, for from 

 them Hagene concludes (op. cit., p. 

 113, free translation) that "this speci- 

 men both establishes the structure of 

 the bundles destined for fructiferous 

 peduncles and confirms the relationship 

 between the genus Mazocarpon and the 

 genus Sigillaria^\ His conclusion ap- 

 parently is based on the close agree- 

 ment between the medullated peduncle 

 steles shown in his section and the ped- 

 uncle stele in the Mazocarpon shorense 

 cone axis illustrated at low magnifica- 

 tion by Benson in 1918. There also is 

 a good general resemblance between the 

 ifledullated steles adequately figured by 

 Hagene and those in Mazocarpon oedip- 

 ternum. 



Hagene 's paper is significant and ex- 



^Stopes and Watson indicate that coal-balls 

 occur at Colne, Lancashire, in a coal below the 

 "First Grit" and presumably different from the 

 Hard Bed horizon. It is thus uncertain, to the 

 author at any rate, whether the Colne Sigillaria 

 is from the Great Coal-ball horizon or one slightly 

 lower in the Lanarkian. 



cellently illustrated, but it seems to 

 have been overlooked by later authors. 

 Hirmer (1927) makes no reference to 

 it. Miss^Calder (1934) also overlooked 

 it in describing two sections from the 

 Kidston collection which seem to have 

 been taken from the same Colne speci- 

 men. The collection data given by Miss 

 Calder agrees with that previously 

 given by Hagene. She reports that the 

 external characters of this stem were 

 exhibited prior to sectioning, and Mr. 

 Hemingway informed her that its iden- 

 tification as Sigillaria elegans was con- 

 firmed at that time by Kidston. Miss 

 Calder 's description in the main agrees 

 with that of Hagene. However, she 

 describes the solid stelar appendages as 

 pertaining to cone peduncles and is 

 undecided as to the nature of the small 

 medullated steles; she makes no ref- 

 erence to Mazocarpon. It seems un- 

 fortunate that sections of this excellent 

 specimen were allowed to become sep- 

 arated. Not only was there duplication 

 of effort, but neither author was able 

 to make a first-hand evaluation of all 

 the evidence. Probably additional in- 

 formation could have been presented 

 had this been possible. 



Graham (1935, pp. 158-161) described 

 a stem from Calhoun coal-balls which 

 he assigned to Sigillaria approximata 

 Font, et I. C. White. Peduncular non- 

 medullated steles are quite numerous 

 in sections of this stem but Graham re- 

 ported none of the medullated type of 

 vascular cylinders found in Mazocarpon 

 oedipternum. The solid steles he de- 

 scribed are somewhat smaller than the 

 solid type steles also present in M. 

 oedipternum cone peduncles. Some of 

 the Mazocarpon oedipternum cones pos- 

 sess a solid stele, but there is little 

 evidence now that specifically similar 

 cones were borne by Graham's Sigillaria 

 approximata, even though both species 

 are from the same horizon. The stem 

 structures described by Graham agree 

 in general with those first reported from 

 Sigillaria elegans by Kidston (1904), 

 but probably internal as well as definite 

 external differences can be found. 



The histological structure of Sigillaria 

 elegans (not to be confused with the 

 Permian form, Sigillaria menardi which 



