EARLY PENNSYLVANIA!! FLORA FROM WEST-CENTRAL ILLINOIS 13 



Material . — The syntypes of Newberry (l'873.) are in the collection 

 of the New York Botanical Garden (NYBG). The "best-preserved specimen 

 (NYBG 59ll+ G) is the one figured by Newberry (l8T3) on plate k6 9 figure 

 3. Specimen NYBG 8320 G is figured on plate k6 9 figure 1. The speci- 

 men of plate k6 9 figure 2, could not be located. The specimens from the 

 Spencer Farm Flora have the ISM numbers 1*16509 , 1*16530, 1*16531, l*l61*3l* 9 

 1*161*50, kl6k51 9 1*161+52, and 1*161*53. 



Discussion . — Newberry (1873) recognized that this species did 

 not belong in the form genus Odontopteris . He believed, however, that 

 he should not make a new genus on the basis of one species. His descrip- 

 tion mentions that two veins enter the pinnules, and in plate 1*6, figure 

 2a, he even shows three veins originating on the pinna rachis. Examina- 

 tion of the syntypes shows that only a single vein enters the pinnules 

 and gives rise to one or two lateral veins. The splitting up of the 

 larger pinnules seems to occur along the veins, indicating that the 

 splitting is a post-mortem phenomenon. 



Newberry (1873) mentioned a fertile specimen (NYBG 1970). The 

 specimen is small and does not preserve a sporangial or pinnule struc- 

 ture. It cannot be definitely identified. The pinnae are 3.5 mm wide 

 and strap shaped and can therefore be compared with A. gracillima. 



Alloiopteris gracillima has a close similarity to A. plumosae- 

 formis 9 which was described by Gothan (I9I+I) from the Namurian B of 

 Germany. In A, plumosaeformis , however, the pinnules are smaller and 

 the tips of the pinnules are blunt. Gothan compares A. plumosaeformis 

 with A. sternbergi, which is, however, distinctly different by virtue 

 of the rectangular insertion of the pinna at the pinna-bearing axis. The 

 same is true for A. erosa (Lesquereux, 1880, pi. 1*1*, fig. l) , which fur- 

 thermore has concavely rounded recessions between the pointed lacerated 

 tips instead of acute tips like those in A. gracillima. A. thinnfeldi- 

 oides has larger pinnules and wider pinnae, but its outline is similar 

 to that of A, gracillima. A. radstockensis is similar to A, gracillima 

 in general aspect and in the fact that the vein dichotomizes shortly 

 after entering the pinnule. The two are different, however, in the 

 shape of the pinnule; A. radstockensis has rounded lobes, which do not 

 occur in A. gracillima. 



Alloiopteris cf. quercifolia 



This specimen (ISM 1*16536) is not preserved sufficiently for a 

 positive identification, but the general character of the well-pronounced 



Text fig. 5 - Fossil plants from the Spencer Farm Flora. A-C, Alloiopteris 

 gracillima, A- basal aphleboid pinnule, B- pinnules in the middle of a 

 pinna, and C- pinnules showing venation pattern and breakup of pinnules 

 along veins. D, reconstruction of one pinnule of Dactylotheca aspera. 

 Bar scales are 5mm long. E, hypothetical steps in the evolution of noeg- 

 gerathialian cones: I- Archaeopteris-1 ike fructification; 2- Noegger- 

 athiostrobus; 3- Lacoea; and 4- Discinites . 



