24 



ILLINOIS STATE GEOLOGICAL SURVEY 



the Rock Island (No. 1) and Murphysboro 

 Coals of die Tradewater Group. They are 

 rare to common in some of the younger 

 coals of the Tradewater. In the Carbondale 

 Group they are common to abundant in 

 some samples of the Colchester (No. 2) 

 Coal (macerations 611, 825, 826), in the 

 Briar Hill (No. 5a) Coal (maceration 633), 

 and in the Herrin (No. 6) Coal (after 

 Schopf, 1938). Only one spore, question- 

 ably referable to T. ragosus, was noted 

 from the McLeansboro Group, that from 

 the "Woodbury" Coal (maceration 703). 



Sectio Lagenicula (?) 



Triletes levis (Zerndt) Schopf, Wilson, 



and Bentall, 1944 



Plate 3, figures 10-14 



1937 Lagenicula levis Zerndt (1937b), p. 587-588; 



pi. 15, figs. 1-11. 

 1944 Triletes levis (Zerndt) Schopf, Wilson, and 



Bentall, p. 23. 



Description. — Megaspores trilete, typical- 

 ly laterally compressed, are characterized by 

 an expanded, high, more or less blunt api- 

 cal prominence (pi. 3, figs. 11, 13). Later- 

 ally compressed spores from 450 to 1300^ 

 in total length, including apical promi- 

 nence (mean 994 /x for 25 specimens). Spore 

 body probably originally spheroidal, hav- 

 ing at least one longitudinal or transverse 

 fold when compressed, from 319 to 978 /x 

 in width and 300 to 927 /x in length. Trilete 

 rays strongly developed, extending nearly 

 to margin of spore body in rare proximo- 

 distal compressions. Lips up to 100 /x in 

 height, as measured from inner surface of 

 spore coat, surmounted by a high apical 

 prominence that is typically slightly con- 

 stricted basally. Apical prominence from 

 129 to 391 p in height, as measured from its 

 basal constriction (mean 278 p for 23 speci- 

 mens), 154 to 494 /x in width, generally 

 slightly wider than high. Apex, measured 

 from inner edge of arcuate ridge, from 247 

 to 752 /x in height or 51 to 62 percent of the 

 total spore length. Contact area approxi- 

 mately equal in area to proximal hemi- 

 sphere of spore body. Arcuate ridges dis- 

 tinct, most noticeable on smallest spores 



(pi. 3, fig. 10). Spore coat up to 97 ^ thick 

 at juncture of arcuate ridge and trilete ray. 



Spore coat generally between 25 ^ and 

 35 /x thick (mean 27.5 /x, range 15 to 41 ^ 

 for 26 specimens). Distal coat smooth or ru- 

 gose to distinctly ornamented with small 

 hemispherical tubercles that are 3 to 10/x 

 in height and 3 to 13 /x in diameter. Inner 

 folded membrane commonly present inside 

 spore body (pi. 3, fig. 12). Spores reddish 

 brown, apical prominence darker than rest 

 of spore by transmitted light but dark and 

 glossy by reflected light. 



Discussion. — All of the above measure- 

 ments were made on spores mounted in bal- 

 sam. Most commonly the spore coat is 

 smooth, the poorly preserved spores appear- 

 ing rugose. However, in the "Watson" Coal 

 (maceration 148), a few spores, otherwise 

 typical of Triletes levis, possess regularly 

 distributed small hemispherical tubercles 

 the larger of which are near the distal pole 

 whereas the smaller and more closely 

 spaced are close to the arcuate ridges (pi. 

 3, fig. 14). 



Recently Dijkstra (1958) described simi- 

 lar spores with comparable ornamentation 

 from the cone of Sigillariostrobus cf. major 

 (Germar) Zeiller that was found in the 

 Lawrence Shale of Kansas. In addition he 

 mentioned that Chaloner found identical 

 isolated spores in this shale. Those few 

 ornamented spores found in the "Watson" 

 Coal are only slightly larger than those de- 

 scribed by Dijkstra and are of approxi- 

 mately the same age. 



Occurring in the "Watson" Coal with 

 these spores are a few smooth-coated spores 

 of Triletes levis. Too few spores were ob- 

 served to determine whether the ornamen- 

 tation is a consistent character on spores of 

 this type in the "Watson" Coal. Nonethe- 

 less, the tubercles are not similar to those 

 irregularly distributed globules, presumably 

 of tapetal origin, described by Felix (1954, 

 p. 359-360) and noted, during the course of 

 this investigation, on some lageniculate 

 spores and on some of the spores of Cysto- 

 sporites. 



Spores of Triletes brasiliensis Dijkstra 

 (1955a, 1956) also possess hemispherical tu- 



