550 THE AMERICAN MIDLAND NATURALIST 



Prof. Noe in 1925 contains a significant statement regarding the relations 

 between Lepidophloios and Lepidocarpon. Mr. Hemingway wrote: 



Lepidocarpon "Lomaxi" represents quite a group of seed-like bodies and cannot yet 

 be separated in sections. Lepidocarpon majus [n. comb.!] has been found attached to 

 stems of Lepidophloios laricinus and Lepidocarpon lanceolatum [n. comb.] to Lepido- 

 phloios acerosus. They are therefore the megasporocarps of Lepidophloios. 



Mr. Hemingway also stated: 



Lepidocarpon Lomaxi represents the "seed" of Lepidophloios — they have been found 

 attached. The so-called species probably represents the seeds of several species of 

 Lepidophloios. Lepidostrohus Oldhamius also represents the microspore cones of Lepi- 

 dophloios and embraces several species. 



It may be that Mr. Hemingway had reference to the leaves at the tip of a 

 vegetative branch of L. acerosus (L. & H.) Kidston (instead of "L. laricinus") 

 that Kidston (1893, pp. 553, 559) illustrated and compared with Lepidophyllum 

 majus Brongniart, and to the lanceolate leaves Macfarlane (1883) associated 

 with Lepidophloios laricinus {^scoticus Kidston). If so, these associations 

 perhaps have value only as analogies. Mr. Hemingway, however, has evidently 

 also noted the lepidocarp characters commonly associated with the majus type 

 sporophyll, and others which supported an identification with Lepidocarpon 

 lomaxi. 



A few obvious lines of investigation suggest themselves for obtaining addi- 

 tional evidence. To judge by the earlier papers of Kidston and others the cones 

 of Lepidophloios scoticus are not rare. Even though they all may be immature 

 when intact, evidence of the spores should be obtainable from them upon 

 maceration. An attempt should be made to obtain compression specimens of 

 Lepidocarpon from the Calciferous Sandstone series where they are to be 

 expected because of their common occurrence as petrifactions. Mr. Heming- 

 way's suggestion that Lepidocarpon lomaxi is separable into more definite 

 species deserves consideration, and if the lomaxi group is reinvestigated, evidence 

 bearing on the relationship of Lepidophloios also should be sought. It is partic- 

 ularly important that the geological longevity of respective diagnostic bio- 

 characters distinguishing the various intimately related species be investigated. 



If the suggested correlation of the genus Lepidophloios with several lepido- 

 carpaceous genera be eventually substantiated it need occasion no great sur- 

 prise. In the main it may be taken to indicate that in this Carboniferous group, 

 as in modern plant groups, reproductive organs in general are more responsive 

 to evolutionary change than are the vegetative ones. 



The oldest members of the lepidocarp family have been reported from the 

 Calciferous Sandstone series of the Lower Carboniferous (Scott, 1900, 1901; 

 also reported from Arran by Walton 1935, p. 318), and Cystosporites appears 

 among the youngest members reported in Stephanian beds of Lower Silesia 

 and the Saar district (recorded as Triletes giganteus; Zerndt, 1937, 1940) . The 

 family is well represented in America both in beds of Pottsville and Allegheny 

 age. Lepidocarpon also has been reported from Calhoun coal balls (Fisher and 

 Noe, 1939) of probable upper Conemaugh age (cf. Schopf, 1941). Diversifi- 

 cation seems more apparent within this family in America than in the old 



