MIDDLE DEVONIAN COAL IN ILLINOIS 



11 



Etymology. — The specific name refers to the rather inconspicuous curva- 

 turae of this taxon. 



Retusotriletes striatus Peppers sp. nov. 

 Plate 3, figures 10-13; text figure 3 



Description. — The spores are radial, trilete, and roundly triangular in out- 

 line but often folded or partially torn. The indistinct rays are simple, straight, 

 and extend about two-thirds the distance to the spore margin. The curvaturae are 

 thin, indistinct, and sometimes visible only with oil immersion objective. The 

 contact area is laevigate and thinner than the distal and equatorial areas. Mar- 

 ginal and transverse to the curvaturae are approximately 100 very fine, closely 

 spaced striations and ridges, 5 to 8 \x long and less than 1 n wide, which may not 

 be visible when viewed with high dry objective. The ridges gradually merge into 

 rows of grana, which in turn merge poleward toward a random distribution of grana 

 that cover the distal and equatorial areas of the exine. The sharply defined grana, 

 which are circular in plan view, are widely spaced, of about equal size, and less 

 than 1 \x in diameter. Thickness of the exine is 1 to 2 \i. Size range (18 speci- 

 mens): 47.8 to 68.6 [i; median, 59 \i. 



x 34 



Holotype 

 0; size, 55 



—Plate 3, figure 10; 

 3 by 51.0 |jl. 



maceration 1510, slide 11, coordinates 141.2 



Paratypes. — Plate 3, figure 11; maceration 1510, slide 12, coordinates 

 122.8 x 33.3; size, 54.9 by 43.9 |a. Plate 3, figure 12; maceration 1510, slide 16, 

 coordinates 133.3 x 47.5; size, 60.8 by 45.5 \±. Plate 3, figure 13; same speci- 

 men as figure 11 but at 1000X magnification to show part of curvaturae. 



Text fig. 3 - Portion of Retusotriletes 

 striatus to show ridges adjacent to 

 curvatura and ornamentation on distal 

 surface . 



Etymology. — The specific name 

 refers to the short ridges and striations 

 around the curvaturae. 



Retusotriletes tenerimedium 

 Chibrikova, 195 9 

 Plate 3, figure 14 



Retusotriletes sp. 

 Plate 3, figure 15 



Description. — The spore is radi- 

 al, trilete, and subcircular in transverse 

 plane. The trilete rays are distinct, ex- 

 tend about two-thirds the length of the 

 spore radius, and are bordered by ele- 

 vated, wavy lips. The curvaturae are 

 conspicuous, thickened, and about 5 ^ 

 wide. The surface of the exine is ver- 

 miculate and obvermiculate, but in the 

 area enclosed by the curvaturae, the 



