22 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 463 



Latosporites minutus Bharadwai, 1957, and Laevigatas po rites perminutus Alpern, 

 1959, are monolete, circular, and more or less smooth, but they are thinner and 

 more often folded than the spores of C 10800. 



? Scolecopteris sp. 2 

 pi. 12, figs. 1, 2, 7-10 



Description.— The spores of specimen C 10803 are trilete and circular to 

 elliptical in transverse plane. Two long laesurae extend about three-fourths the 

 spore radius, but the third laesura is less than one-half the length of the other 

 two. The spore surface is covered with minute papillae and spines that are so 

 closely spaced that parts of the spore surface appear punctate. Sculptural ele- 

 ments are less than 0.5 |xm in diameter and are about twice as long as they are 

 wide. The exine is 1 to 2.5 \im thick. Diameter size range (30 specimens) is 

 from 18 to 24 ^m, with an average of 20 |am. Because of the close spacing of the 

 minute spines, the true nature of the ornamentation is best shown by scanning 

 electron microscopy. Under transmitted light, the exine appears punctate, granu- 

 lose, or papillate. 



Comparison.— The spores from fructification C 10803 are in the size range 

 of Laevigatosporites globosus and are therefore correlated with that species. The 

 surface ornamentation of these spores is similar also to that of Punctatisporites 

 obliquus Kosanke, 1950, and £. orbicularis Kosanke, 1950. Habib (1966) and 

 Peppers (1970) noted that L. globosus is similar to P. obliquus except that it is 

 smaller, has a shorter third ray, and is more ellipsoidal than_P. obliquus . The 

 spores of specimen C 10803 are apparently more circular than typical specimens 

 of Laevigatosporites globosus , but this difference is probably the result of dif- 

 ferences in preservation. It is conceivable that they represent immature speci- 

 mens of Punctatisporites obliquus , but the minimum size range of the latter is 

 about 7 jim greater than the maximum size of the spores in specimen C 10803. The 

 ornamentation of the spores in situ is well developed for immature spores. 



Potonie and Kremp (1954) placed Laevigatosporites globosus in the genus 

 Latosporites Potonie and Kremp, 1954, which is reserved for monolete spores hav- 

 ing laevigate to infrareticulate exines. Examination of specimens of Laevigato- 

 sporites globosus under oil immersion objective reveals that the ornamentation is 

 minutely papillate to spinose but that it appears to be punctate or infrapunctate 

 where the projections are closely packed. L. globosus is a species that is com- 

 monly present in the Illinois Basin from the top of the Abbott Formation to the 

 lower part of the Mattoon Formation. 



Discussion 



The two fertile compressions resemble very much the genus Danaeites . 

 The longitudinal striation of each fructification, however, and the missing sub- 

 divisions of the spore masses exclude the genus Danaeites. The specimens re- 

 semble more closely some species of Scolecopteris in which the sori are inclined 

 towards the midvein (text fig. 9). This inclined position has been reported in 

 S. minor Ho skins, 1926, and in S. incisifolia Mamay, 1950, from coal balls 

 (Graham, 1934; Mamay, 1950). None of these species can be directly compared 

 with the specimens described here, because of differences in the size of pinnules 

 and fructifications. Our specimens correspond in size, however, with_S. oliveri 



