EQUISETOSPORITES 



47 



known from American coals and will sub- 

 sequently be described. The numerous 

 spores illustrated by Reinsch (1884) in the 

 Micro-Paleophytologia show best the vari- 

 ation in structure encountered is this 

 group. The spores with highly exag- 

 gerated angular thickenings were mostly 

 derived from localities in Russia where 

 the coals probably are of Lower Carbonif- 

 erous age. Dio and D^ types of Raistrick 

 (1938) were chiefly obtained from the 

 Lower Carboniferous of England. Penn- 

 sylvanian age species are much more 

 moderate in spore coat thickness and the 

 interradial and distal membranes are fre- 

 quently less than 3 microns thick, as in 

 the four species which have been de- 

 scribed and named. The angles are more 

 than twice as thick, however, and their 

 relationship thus seems definitely indi- 

 cated. Nevertheless, it may be desirable 

 that the thicker walled more ornate and 

 radially extended forms be generically 

 segregated when detailed modern infor- 

 mation becomes available for the older 

 species. The tendency toward seeming 

 simplification in spore coat structure of 

 late Carboniferous plants as contrasted 

 with ealier merpbers of the same alliance 

 has also been noted in members of the 

 Lagenicula and Aphanozonateae sections 

 of Triletes. 



1. Triquitrites arculatus Wilson and Coe, 

 1940, Am. Midland Naturalist, vol. 23, no. 

 1, p. 185, fig. 8. 



Note. — Type material bears a moderate to 

 sparse verrucose flecking (areas of thickening) 

 on proximal and distal surfaces, possibly due to 

 overmaceration. 



2. Triquitrites spinosus Kosanke, 1943, Am. 

 Midland Naturalist, vol. 29, no. 1, p. 128. 

 pi. 3, figs. 2, 2a, 2b. 



3. Triquitrites tribullatus (Ibrahim) S. 

 W. and B., comb. nov. 



Sporonifes tribullatus Ibrahim, 1932, 

 Neues Jahrb., Beilage-Band 67, Abt. B, 

 p. 448, pi. 15, fig. 13. 



Laevigati-sporites tribullatus (Ibrahim) 

 Ibrahim, 1933, Sporenformen des Aegirhor- 

 izonts, pp. 20-21, pi. 2, fig. 13. 



Valvisi-sporiies tribullatus (Ibrahim) 

 Loose, 1934, Inst. Palaobot. Arb., vol. 4, 

 no. 3, p. 152, pi. 7, fig. 21. 



4. Triquitrites trigonappendix (Loose) S. 

 W. and B., comb. nov. 



Valvisi-sporites trigonappendix Loose, 

 1934, idem, p. 152, pi. 7, fig. 17. 



5. Triquitrites triturgidus (Loose) S. W. 

 and B., comb. nov. 



Sporonites triturgidus Loose, 1932, 

 Neues Jahrb., Beilage-Band 67, Abt. B, 

 p. 449, pi. 18, fig. 32. 



Valvisi-sporites triturgidus {Loose) 

 Loose, 1934, Inst. Palaobot. Arb., vol. 4, 

 no. 3, p. 151. 



Genus Equisetosporites Daugherty, 

 1941 



This genus recently described from Tri- 

 assic age beds in southwestern United 

 States is mentioned here because of its 

 important bearing on recognition of fossil 

 spores of certain Equisetalean plants. The 

 genus is monotypic, including only E. 

 chinleana as given below, whose note- 

 worthy feature is the presence of elaters 

 very similar to those characterizing the 

 modern genus. The vahdity of the name 

 Equisetosporites rests on the belief that 

 these forms should be distinguished from 

 spores of Equisetum. It appears there is 

 adequate support for this view since 

 Daugherty, in a personal communication, 

 states "in all cases Equisetum-like. plants 

 of the Triassic have proven to be quite dif- 

 ferent when the record is complete enough 

 to allow specific determination." Thus 

 until further evidence is available, it 

 would seem unwise to emphasize the mod- 

 ern aspect of this fossil form. Its dis- 

 covery nevertheless adds an important 

 item of information to the record. 



Knox examined spores of fifteen species 

 of Equisetum and reports (1938, pp. 439- 

 40) them to be invariably spherical, 30 

 microns to 35 microns in diameter, and 

 always thin walled. In all these species 

 the spore wall was faintly granular. Ela- 

 ters of somewhat varied character are 

 present on all modern species of Equi- 

 setum. In commenting on Raistrick's Bg 

 type, which she recognizes is very prob- 

 ably of calamarian affinity, Knox remarks 

 (pp. 461-3) on 



the same globose form with thin wall and 

 absence of ornamentation . . . the unusual de- 

 velopment of elaters and no trace of the tri- 

 radiate mark. 



She cites Halle's description of Rhaetic 

 and Triassic - age Equisetuni spores 

 (Halle, 1908) in which the trilete com- 

 missure is clearly seen but which show 

 no trace of elaters. Halle assumed that 

 even if elaters had been present they 

 would have been removed by maceration 

 procedure. Needless to say, this aspect 



