4° 



MORPHOLOGY OF GYMNOSPERMS 



41 '*3 42 



Figs. 41-43. — Aneimites jertilis: 

 fig. 41, fragment of pinna with seed 

 {s); fig. 42, seed on long pedicel 

 connected with foliage; fig. 43, seed 

 showing wings, the latter somewhat 

 exaggerated; X2. — After White 

 (49). 



development, are associated with Aneimites in most of the deposits 



observed (Lower Pottsville of the Virginia region), and have been 



found in organic connection with the fronds of two species. They 



seem to represent a very different type 

 of seed (platysperms) from those found 

 in connection with Lyginodendron and 

 Medullosa. 



Pecopteris. — In 1905 Grand 

 'EuRY (52) announced the discovery 

 of seeds on P. Pluckenetii. A mass of 

 sterile and fertile pinnules was found, 

 the latter bearing hundreds of seeds. 

 These are not borne at the extremities 

 of naked branchlets, the seed-bearing 

 pinnules being very slightly modified 

 and bearing a seed hanging freely at 



the extremity of the principal veinlet of each lobe (fig. 44). Scott 



(58) speaks of this as " the most striking instance of a 'seed-bearing 



fern' yet brought to light." The seeds are 



small (about 5 mm. long), oval, and with 



narrow wings. The winged habit of these 



seeds and of the seeds of Aneimites suggests 



the seeds of Cordaitales, and it becomes 



evident that fossil seeds can no longer be 



assigned with certainty except on evidence 



of organic connection. The discovery that 



a species of Pecopteris was a seed-bearing 



plant was one of very great interest, for it 



was the last great frond genus to join the 



Cycadofilicales, and it is the most con- 

 spicuous genus in the variety of sporangia 



it bears. 



Probable seeds of Cycadofilicales.— 



In the preceding cases the evidence of the 



seed-bearing habit is direct and convincing; 



but in addition there is a possible range of inferences that are worth 



considering. Grand 'Eury (53) has called attention to the great 



Fig. 44. — Pecopteris 

 Pluckenetii: portion of fer- 

 tile pinna with seeds at- 

 tached at ends of lobes 

 of pinnules; X3. — After 

 Grand 'Eury (43). 



