TASMANITES 



13 



lacious idea of the primitiveness of that 

 group of living plants, current at the 

 time, and on the other by association with 

 the (probably unrelated) thalloid plants 

 sometimes found in the same beds. Daw- 

 son considered his study of the Brazilian 

 material particularly conclusive but his 

 account of it does not seem so now and, 

 unless the original material can be re- 

 studied or new material obtained, the spe- 

 cific nature of the Brazilian specimens is 

 entirely problematic. 



Jongmans more recently (1930) has 

 listed most of the nomenclature rather 

 indiscriminately under the name Proto- 

 salvinia. His treatment is hard to com- 

 prehend inasmuch as Sporangites and 

 Tasmanites are treated as synonyms 

 although their precedent publication dates 

 are given with approximate correctness." 

 In attempting to follow Dawson's some- 

 what confused usage and apply it more 

 widely without original study, Jongmans 

 has not contributed to the understanding 

 of these plants or lessened the confusion 

 in nomenclature. His omission of some 

 pertinent references may in part be re- 

 sponsible for the rather misleading im- 

 pression conveyed by this portion of the 

 Catalogus. 



One other thalloid plant occurs in asso- 

 ciation with sporangite forms in the black 

 shale which now can be more adequately 

 discussed because of reexamination by 

 modern methods. Spores are present in 

 it and are quite different from sporangite 

 bodies, in spite of Dawson's suggestion 

 that they were similar. Dawson (1888) 

 called this form Sporocarpon furcatum. 

 In the most thorough and essentially 

 definitive study of this plant by Kidston 

 and Lang (1925), Dawson's name was 

 continued. However, White, in White 

 and Stadnichenko (1923), had renamed 

 the group Foerstia but without taxonomic 

 comment or discussion. Nevertheless the 

 reason and justification for this new gen- 

 eric name is evident upon consideration 

 of the genus Sporocarpon Williamson 

 (1879, cf. also 1880, p. 509) which was 

 founded upon .S. cellulosum and similar 

 forms of problematic affinity but quite 



f Dawson's paper in the Canadian Naturalist for 1870 

 evidently appeared subsequent to publication of his paper 

 in the Am. Jour. Sci. for April, 1871. The paper "On 

 Rhizocarps, etc." published in the Canadian Record of 

 Science is dated and evidently was published in 1884, 

 rather than 1885. Such minor errors are unfortunate in a 

 reference so widely used as the Fossilium Catalogus. 



definite morphologic character. Many 

 have considered the Sporocarpon types to 

 be lycopod megaspores but from our pres- 

 ent knowledge such a view seems un- 

 tenable. Their structure is more rem- 

 iniscent of colonial habit seen in the 

 Volvocales. At any rate, there is no 

 similarity between them and Sporocarpon 

 furcatum Dawson. The name for this 

 form must be Foerstia furcata (Dawson) 

 Pia; Pia (1927) having been first to use 

 this combination, but also without com- 

 ment. The type species of Foerstia is 

 best taken to be Foerstia ohioensis White, 

 instead of Dawson's species. Kidston 

 and Lang's work suggests that they may 

 be specifically inseparable and if this is 

 ever proved by comparison of the holo- 

 types of the two species, White's specific 

 designation, F. ohioensis, of course would 

 become a synonym. 



The spores of Foerstia occur in tetrads, 

 to some extent localized along one margin 

 within the fertile tips. Possibly they were 

 formed in individual conceptacles. An 

 analogy in more than one particular is 

 suggested by Fucus, but aside from the 

 possibility that Foerstia may also be an 

 advanced type of alga, probably no inter- 

 pretation of homology can be supported. 

 The individual spores of Foerstia are 

 about 200 microns in diameter, similar to 

 those of land plants, with a heavy "re- 

 sistant" spore coat about 7 microns thick, 

 definite haptotypic structures consisting 

 of trilete sutures with pyramic areas well 

 defined by distinct arcuate ridges. The 

 distal part of the spore coat is irregu- 

 larly pitted and somewhat rugose accord- 

 ing to information presented by Kidston 

 and Lang. Thus, these spores are en- 

 tirely different from the sporangite bodies 

 that may be associated with them. 



Haptotypic features have been de- 

 scribed for the spores in all reliable 

 reports that have ever been published of 

 bonafide Devonian plants showing these 

 reproductive structures. These spore 

 forms, in addition to Tasmanites and its 

 associates, may be found isolated in car- 

 bonaceous Devonian sediments. Lang 

 (1925) has shown that eight or more 

 distinct species are thus represented in 

 the Cromarty fish-beds of Old Red Sand- 

 stone age in Scotland. None of these 

 can be referred to Tasmanites, although 

 Lang's spore-type F (in part), which 



