GENUS TRILETES 



25 



bercles 5 to 30 /x in diameter. Although the 

 spores are similar in general appearance to 

 spores of T. levis, they have a more robust 

 development of the trilete rays and arcuate 

 ridges. The apical prominence is distinctly 

 pyramidal in shape. The spores also are 

 younger, occurring in the Lower Permian 

 coals of Brazil (Dijkstra, 1956). 



Although Dijkstra (1946) considered 

 Triletes levis (Zerndt) Schopf, Wilson, and 

 Bentall as a later synonym of T. nudus 

 (Nowak and Zerndt) Schopf, these spores 

 from the younger Pennsylvanian coals of 

 Illinois are very similar to those originally 

 described as Lagenicala levis by Zerndt 

 (1937b, p. 587-588, pi. 15) from the West- 

 phalian E (according to Dijkstra, 1946) of 

 Bohemia and by Pierart (1956) from the 

 Middle Stephanian of France. 



The megaspores described here are re- 

 ferred to Triletes levis although they have 

 a slightly thicker spore coat than those de- 

 scribed by Zerndt. There is no information 

 regarding the appearance of Zerndt's speci- 

 mens under transmitted light. The general 

 shape and dimensions of the Illinois spores 

 apparently are identical to those illustrated 

 by Zerndt (1937b, pi. 15). Especially typi- 

 cal of the Illinois spores are the shapes illus- 

 trated by Zerndt (1937b, pi. 15, figs. 1, 6, 9) 

 in which the apical prominence is blunt to 

 rounded and rises abruptly from the lips. 

 The spore illustrated by Nowak and Zerndt 

 (1936, pi. 1, fig. 6) and originally desig- 

 nated as Lagenicula nuda appears to have 

 a broader apical prominence, relative to 

 spore size, which rises from the lips closer 

 to the radial extremities, and a more oblate 

 body form. At present the spores of T. levis 

 are known only from coal beds in the Mc- 

 Leansboro Group, whereas spores more sim- 

 ilar in appearance to those of T. nudus 

 were noted in a thin coal bed (maceration 

 455) from a sinkhole deposit of possible 

 early Pennsylvanian age. 



Schopf (1938, pi. 5, fig. 7) described some 

 spores, of rare occurrence in the Herrin 

 (No. 6) Coal of the Carbondale Group, that 

 he questionably referred to Triletes nu- 

 dus. The illustrated spore has a rugose 

 coat. The apical prominence is not dis- 



tinctly darker, by transmitted light, than 

 the remainder of the spore. Schopf, Wilson, 

 and Bentall (1914, p. 23) noted that this 

 form is probably not referable to T. nudus 

 although the shape is similar. Neither are 

 these spores similar to those referred here 

 to T. levis. However, on the distribution 

 chart, the spores described by Schopf are 

 noted under his original designation, Tri- 

 letes (?) nudus. 



Cross (1947, p. 287, fig. 2; pi. Ill, figs. 

 100-104; p. 305) described spores, desig- 

 nated as Triletes nudus (Nowak and 

 Zerndt) Schopf, that appear identical to 

 those described here as T. levis. Cross notes 

 their occurrence only in the Waynesburg 

 Coal of the Monongahela Series of the Ap- 

 palachian Basin. Thus the Illinois and Ap- 

 palachian Basin spores are similar in ap- 

 pearance, although the spores Cross de- 

 scribed are from a somewhat younger coal. 



Affinity. — Potonie and Kremp (1955) 

 noted that the alliance of the lageniculate 

 spores is with the Lepidodendraceae. Lyco- 

 spora-type microspores are known to be the 

 microspores associated with many of the 

 lageniculate megaspores (Chaloner, 1953b; 

 Potonie, 1954a, b; Felix, 1954) and with 

 those of Cystosporites (Felix, 1954). How- 

 ever, in the McLeansboro Group, abundant 

 lageniculate spores occur (Triletes levis), 

 but they are not accompanied by Lycospora- 

 type microspores (Kosanke, 1947, 1950). 

 Therefore T. levis is referred questionably 

 to the section Lagenicula. Recently similar 

 spores have been discovered (Dijkstra, 

 1958) in Sigillariostrobus. 



Occurrence. — These spores are rare in the 

 "West Franklin" Coal (maceration 831a) , 

 Indiana, in the Macoupin Coal (macera- 

 tion 561) of Bond County, in the "Divide" 

 Coal (maceration 811), and in the Friends- 

 ville Coal (macerations 135, 153, and 

 490D). They occur abundantly in the 

 Friendsville (?) Coal (maceration 136) from 

 Wabash County, Illinois, in the "LaSalle" 

 Coal (maceration 600), and in a coal (mac- 

 eration 146) in the Merom Sandstone. Ap- 

 parently they are less abundant in the 

 "'Watson" Coal (maceration 148) and in 

 the "Woodbury" Coal (maceration 703). 



