EARLY PENNSYLVANIA FLORA FROM WEST-CENTRAL ILLINOIS 33 



The sterile foliage shows certain similarities to Rhodeopteridium 

 tenue (Gothan) Purkynova" (1970). However, R. phillipsii is strictly pin- 

 natifid and shows a much more regular construction of the leaf. 



Holcospermum sp. 

 Text fig. 12A; pi. lk 9 figs. 6, 7 



A single fragment of this genus has been found; it is 12 mm wide 

 and is preserved to a length of 10 mm, but it is obvious that this is 

 less than one-half the original length. The nucule was probably ovoid- 

 elongate and radially symmetrical. The four visible ribs are 0.5 mm 

 wide; eight were probably present around the entire circumference. This 

 fragment is similar to specimens of H. mansfieldi figured by Arnold 

 (19^9, pi. XXIX, fig. 2) from Michigan and by Wood (1963, p. 11, fig. 3) 

 from Indiana. 



CORDAITALES 

 Cordaites cf. principalis 



PI. 15, figs. 1, 2 



Cordaites leaves are a common element in the Spencer Farm Flora. 

 However, they are fragmentary and poorly preserved. The surface is 

 marked by coarse linear ribs separated by one to three fine ribs. The 

 striation is the only characteristic on which the tentative identifica- 

 tion can be based. 



Platyspermic Seeds 



Two of the most commonly encountered genera of the platyspermic 

 seeds are Samaropsis and Cordaicarpus. Samaropsis Goeppert includes im- 

 pressions of flat, more or less circular seeds. The seed is surrounded 

 by an oval or heart-shaped border called a wing, which is formed by the 

 soft tissue of the sarcotesta. Cordaicarpus Geinitz includes seeds that 

 are similar to Samaropsis , but that do not possess a definite sarcotesta 

 or that show only a very narrow one. Table 6 gives the available data 

 about the specimens, which are classified on the basis of overall shape. 

 It should be pointed out that the Cordaicarpus sp. B and the "miscella- 

 neous nucelli" may in fact be parts of other forms, separated only be- 

 cause of incomplete preservation. 



The platyspermic seeds are treated under Cordaitales because 

 some of them belong to Cordaites. It should be realized that a connec- 

 tion has not been shown in most cases and that the arrangement is partly 

 a matter of convenience. 



Samaropsis sp. A 

 Text fig. 12B;pl. 15, figs. 5, 6, 7 



These seeds are large, ovate to heart-shaped with a wide wing. 

 In the better preserved specimen (pi. 15, fig. 6), the base is cordate 

 and the nucellus is marked with lines roughly paralleling the margin. 

 Also visible on this specimen is a V-shaped slit at the apex of the sar- 

 cotesta. On one specimen (pi. 15, fig. 5), a fairly wide (0.5 mm) line 



