32 



ILLINOIS STATE GEOLOGICAL SURVEY 



tance between the outer margins of the 

 "ears." Potonie and Kremp distinguish 

 these spores from those of T. auritus on 

 the basis that the equatorial distance be- 

 tween "ears" is shorter. The spores are dis- 

 tinguished from those of T. trilobus on the 

 basis that the equatorial distance between 

 "ears" is longer. The distinctions between 

 the three species may or may not have 

 taxonomic significance. 



Potonie and Kremp (1956) report that 

 Triletes appendiculatus can occur in the 

 Westphalian A-D in various coal basins. 



The "ears" of the illustrated spore (pi. 

 7, fig. 14) are up to 410 /x in width and 

 250 (x in length. The "ears" are poorly pre- 

 served and folded; originally they were 

 probably longer. The trilete rays are similar 

 to those on spores of Triletes auritus in 

 that they are thin, extend to the "ears," 

 and possess an abruptly upraised portion 

 at the apex. The "ears" of another speci- 

 men were up to 470 ^ in width. The spores 

 are rare and generally occur with spores of 

 T. auritus. 



Occurrence. — This species is represented 

 by a few spores found in the Tarter Coal 

 (maceration 604A) and in the lower coal 

 (maceration 950A) from Goose Lake, 

 Illinois. 



Triletes (Auriculati) spp. 



Plate 7, figures 15-18 



Some of the other types of auriculate 

 spores noted during this study are illus- 

 trated in order to give an over-all picture 

 of the variability between spores referred 

 to the section Auriculati. 



The spore shown on plate 7, figures 15a 

 and 15b, is similar to those of Triletes au- 

 gustae in general morphology but is much 

 larger — 1900^ in maximum diameter. An- 

 other large auriculate spore (pi. 7, fig. 16) 

 from the same sample has undulatory arcu- 

 ate ridges and a distinct pattern of small 

 depressions or pits on the contact areas. Of 

 the two illustrated from coals of the 

 McLeansboro Group, that shown on plate 

 7, figure 17, might be referred, by some, to 

 T. augustae. The other (pi. 7, fig. 18) has 

 heavy rays, pitted contact areas, and undu- 

 latory arcuate ridges. No spores resembling 



those of T. tuberculatus were noted during 

 this study. 



Sectio Zonales (Bennie and Kidston) 

 Dijkstra, 1946 



Spores in the Zonales section (Dijkstra, 

 1946) are of average to large size and pos- 

 sess an equatorial rim provided with an 

 equatorial zone. Some of the spores possess 

 zones or flanges consisting of anastomosing 

 processes. The ornamentation, according to 

 Dijkstra, is of perisporal origin. These 

 spores are much larger than those of the 

 section Triangulati. 



The zonate megaspores occur in coal 

 beds in the Caseyville and Tradewater 

 Groups, but are most diversified and con- 

 spicuous in the older coals in the Trade- 

 water Group. None has yet been found in 

 coals in the Chester Series or in coals in the 

 Carbondale and McLeansboro Groups. 

 However, Chaloner (1956a) describes a 

 fructification containing zonate megaspores 

 found in a shale above the Colchester (No. 

 2) Coal of the Carbondale Group. 



Triletes rotatus Bartlett, 1929 

 Plate 8, figures 1, 2 



1929 Triletes rotatus Bartlett, p. 21; pi. IX; pi. X, 



figs. 1,2; pis. XI, XII. 

 1937 Triletes rotatus Bartlett, in Zerndt (1937a), 



p. 8-10; text fig. 6; pis. 6-10. 

 1946 Triletes rotatus Bartlett, in Dijkstra, p. 42- 



43. 



1954 Rotatisporit.es rotatus (Bartlett) Potonie and 

 Kremp, p. 163; pi. 15, fig. 65. 



1955 Rotatisporites rotatus (Bartlett) Potonie and 

 Kremp, in Horst, p. 189-190; pi. 18, figs. 10- 

 14. 



1956 Rotatisporites rotatus (Bartlett) Potonie" and 

 Kremp, in Potonie and Kremp, p. 135; text 

 fig. 59. 



Discussion. — Some spores of Triletes ro- 

 tatus, many of which are fragmentary, are 

 found in the coal beds of Illinois. In com- 

 parison to those of T. ramosus, they are 

 smaller (720 to 815 ^ in diameter) , have a 

 thinner spore coat (20 to 30 ^ distally, 12 p 

 proximally) , and similar lip development. 

 The spores are characterized by an encir- 

 cling flange consisting of a single row of 

 straplike appendages (pi. 8, fig. 2) that ex- 

 tend from the spore body, are somewhat 

 proximal to the geometrical equator, and 



