40 THE OLDER MESOZOIC FLORA OF VIRGINIA. 



pinnules. Sori on the pinnules of the lowest pinnae few, and often single, irregularly 

 grouped ; those of the pinnules of the upper part of the frond more numerous, and at 

 most 2 to 3 on each side of the midrib. 



This small plant has a striking likeness to the Gleicheniaceae in the 

 smallness of the pinnules, their coriaceous character, and the small number 

 of sori, which in the lower pinnules are often single on a pinnule, or one on 

 each side of the middle nerve. The leaf substance is so dense that no trace 

 of the nerves, except the middle nerve, can be made out. The sori are very 

 large in proportion to the size of the pinnules, and increase in number from 

 the lower to the upper portions of the plant. The very considerable dis- 

 tance apart of the pinnules is a noteworthy feature. They are frequently, 

 especially in the middle and upper parts of the plant, placed at a greater 

 distance apart than half the width of the pinnules. Plate XV, Fig. 1, rep- 

 resents what is evidently a portion of a very long and slender frond or 

 primary pinna. From the rigid and stout character of the primary and 

 secondary rachis, it would seem to be a primary pinna from some large 

 frond. 



It is strikingly like Gleichenites microphyllus, Scbenk, from the Rhpetic 

 of Germany, see "Flora der Grenzschicht," plate xxii, figs. 7, 8. The 

 only difference is that the pinnules of the Virginia plant are more remotely 

 placed. In this point it is nearer to Heer's Pecopteris gracilis, from the Trias 

 of Europe. Schenk says that he would have considered his plant as iden- 

 tical with that of Heer, were it not that his observations showed that none 

 of the plants of the Trias were identical with any of those of the Rhaetic. 

 This, I think, is not a sufficient reason for separating them. At any rate, 

 our plant is very closely allied to both of these. 



Formation and locality. — Very rare at Clover Hill, in argillaceous, flaggy 

 sandstone, probably from above the main coal, and associated with the 

 group of small coal beds. 



Asterocaepus, Goeppert. 



I place, with a. good deal of hesitation, the following two species in 

 Goeppert's genus Asterocarpus. They have some resemblance to the plants 

 grouped as Mertensides, but on the whole seem to approach nearer to the 



