EARLY PENNSYLVANIA^ FLORA FROM WEST-CENTRAL ILLINOIS 25 



Megalopteris minima has a venation which is very similar to that 

 of M. ovata. Another species that seems to be closely related to M. ovata 

 is Megalopteris abbreviata. 



Lesleya cheimarosa sp. nov. 

 Text fig. 8C, F; pi. 6, fig. 5; pi. 8, figs. 1-3 



Description . — Simple leaf of considerable size, about 20 cm long 

 and k cm vide, lanceolate with acute to attenuate tip. Base long and 

 narrow (acuminate). Margin entire. Venation pinnate, midrib thick, 0.7 

 to 2 mm wide; lateral veins fork once or twice; lateral veins S-shaped 

 with a 10° to 20° angle at the midvein, 30° to 70° angle in center, and 

 k0° to 70° angle on margin; 2k to 36 veins per cm on margin. 



Holotype : ISM 4161+88 a, b, on pi. 8, figs. 1, 2 



Paratypes : ISM 1+16508, I+I6526 



Derivation of name : From the Greek x £ iy a PP° s ( = cheimarros), 

 periodical floods in rivers. 



Discussion . — Lesleya cheimarosa is fairly common in the Spencer 

 Farm Flora but only one complete leaf has been found so far. In text 

 figure 7E the variation of the shape of the lateral veins on the holo- 

 type is shown. The density of the veins also differs in different parts 

 of the lamina. It is not certain whether the asymmetrical base is typi- 

 cal or is, rather, a result of preservation. 



This species is attributed to the genus Lesleya because the leaf 

 is simple and not part of a compound frond. Lesleya was first described 

 from Illinois from the level of the Rock Island (No. l) Coal Member. 

 All subsequent discoveries, however, were reported from France and Italy 

 from beds of Westphalian D, Stephanian, or Permian age. The oldest form 

 reported outside the United States is Lesleya weilerbachensis Remy and 

 Remy ( 197 5a) from the upper Westphalian C of the Saar area in Germany. 



Alethopteris lonchitica (Schlotheim) Sternberg 

 Text fig. 9A-D; pi. 9, figs. 1-6 



Description . — Pinnules linear-lanceolate or oblong, length to 

 width ratio between 2.3:1 and 5:1 (average 3.2:1, based on Ik specimens); 

 apex obtuse to acute; base decurrent on the proximal side and deeply in- 

 cised on the distal side, both features highly variable in shape. Pin- 

 nules not connected with each other in lower parts of pinna, but become 

 confluent towards the apex. Pinnules attached obliquely 25° to 85° 

 (average about 60°). 



Midvein thick, nearly reaching the apex. Lateral veins varied 

 in their form, normally forked once, rarely simple or forked twice; their 

 angle at the midvein ranges from 30° to 75° (average 50°); their angle 

 with the margin ranges from I+5 to 90° (average 70°). There are 32 to 

 50 veins per cm on margin (average ko) . 



