44 



ILLINOIS STATE GEOLOGICAL SURVEY 



feebly granulated. Triradiate ridge promi- 

 nent, occupying about four-fifths of the 

 upper surface, between the arms of which 

 are radiating flexuous lines that usually ex- 

 tend to the curved line that connects the 

 arms of the central three-rayed star." 



Occurrence. — Triletes globosus var. (A) 

 is abundantly represented in the coal in 

 the Mississippian (lower Chester) Har- 

 dinsburg Formation (maceration 810), 

 Kentucky, and present in the Waltersburg 

 Formation, Randolph County, Illinois. 



Triletes globosus Arnold var. (B) 

 Plate 4, figures 4-10 



Description. — Megaspores trilete, gener- 

 ally proximo-distally compressed, ranging 

 in diameter from 390 to 640 ll (mean 545 fx 

 for 33 specimens) . Trilete rays increasing 

 in height, a little less abruptly than on 

 spores of Triletes globosus var. (A) , up to 

 100 [a at apex and forming an apical promi- 

 nence (pi. 4, fig. 4) about 100 fx in width. 

 Length of trilete rays between two-thirds 

 and three-fourths the radius of the spore 

 body. Contact areas covered with conspicu- 

 ous small pointed spines up to 5 fx in 

 length. Spore body containing crumpled, 

 apparently unornamented inner membrane. 



Distal coat covered by an irregular net- 

 work of catenulate-type spines (pi. 4, figs. 

 6, 8, 9) , rather bulbose near tips, terminat- 

 ing abruptly in a sharp point. Spine length 

 from 15 to 57 ju, generally more than 35 p, 

 spines forming a rather solid flange, crenu- 

 late only at margins (pi. 4, fig. 10), up to 

 56 p in width. 



Spore coat commonly less than 16 /x thick 

 distally, several microns thinner at contact 

 areas, orange to reddish brown by trans- 

 mitted light. 



Discussion. — These spores differ from 

 those of Triletes globosus var. (A) in hav- 

 ing a less abruptly formed apical promi- 

 nence, slightly snorter rays relative to body 

 size, longer spines, a more prominent de- 

 velopment of the arcuate flange, and a more 

 conspicuous development of spines on the 

 contact area. 



Similar appearing spores, possessing gen- 

 erally shorter spines, also occur abundantly 



in the upper coals of the Wabash County 

 core and in the French Lick and Pinnick 

 Coals of Orange County, Indiana. The dis- 

 tal appendages of these spores are generally 

 15 to 25 ix long, principally discrete rather 

 than joined, and pointed. A flange is de- 

 veloped around the arcuate ridge. Some 

 specimens are obviously abraded (pi. 4, fig. 

 7) . It would seem that all these are more or 

 less abraded specimens of Triletes globosus 

 var. (B) , the catenulate joinings and tips 

 of distal spines having been removed. The 

 spores range from 360 to 565 fx in diameter 



(mean 487 /x) ; the apical prominence is up 

 to 72 fi in height and the coat is 15 to 20 jx 

 thick. The major difference between spores 

 of T. globosus var. (B) , where typically 

 developed in the lowest coal of the Wabash 

 County cores, and those in the upper coals 

 is that the latter have more discrete and 

 pointed spines, possibly a preservational 

 feature. Some of the abraded specimens are 

 difficult to distinguish from the abraded 

 specimens of T. globosus var. (A) . 



Spores of Triletes globosus var. (B) may 

 be comparable to those described by Zerndt 



(1937a) as variety II of type 13a, T. tenui- 

 spinosus var. brevispinosa. Zerndt noted dis- 

 tal appendages 36 to 96 ^ long that are so 

 densely set that some adjacent spines are 

 joined. However, he did not mention any 

 flange development. One of the character- 

 istic features of spores of type 13a is the 

 ridges on the contact areas radiating from 

 the apex. Megaspores of T. globosus var. 



(A) have a vaguely defined ridging, but 

 those of T. globosus var. (B) are not 

 ridged (pi. 4, fig. 5) . 



In his discussion of Triletes praetextus, 

 Cross (1947, p. 302) described spores, des- 

 ignated as T. praetextus var. I, with a very 

 narrow solid flange and noted that they re- 

 semble T. hirsutus except that they do not 

 appear lageniculate. In size and possession 

 of a narrow solid flange they are compa- 

 rable with T. hirsutus var. (B) . Cross 

 noted their importance in coal beds of the 

 Lower Kanawha, and in the Lower War 

 Eagle and Eagle Coals as given on his 

 figure 2. 



Occurrence. — Megaspores of Triletes glo- 

 bosus var. (B) are abundant in the early 



