510 T. D. A. Cocker ell — Descriptions of Tertiary Plants. 



genus. However, Lesquereux figures with his A. longe- 

 petiolata a samara, which he says " may not represent the 

 fruit of the same species, but which is evidently very much 

 like that from Florissant. The seed is more transverse, how- 

 ever ; the venation is not shown. 



Quercus Jcnowltoniana sp. no v. Fig. 4. 



Acorn-cup 30 mm diameter; scales in about 10 rows, triangular, 

 from about the fifth row sharp-pointed, but the more basal ones 

 broad and angled rather than pointed ; no visible marginal 

 fringe. 



Florissant {Mrs. Charlotte Hill). Holotype at Yale Univer- 

 sity, Cat. No. 1005. I bad retained this curious fossil for 

 months, hoping to be able to determine it, but failing to 

 recognize its relationships. Dr. F. H. Knowlton recently visited 

 my laboratory, and upon showing the fossil to him, he at once 

 recognized what it was. Now that the fact has been pointed 

 out it is so evident that the specimen is an acorn-cup that I do not 

 understand my obtuseness on the subject. The species recalls 

 the recent Q. macrocarpa Michx., the cups of which grow to 

 an even larger size. I have no leaf from the shale that I can 

 refer to it. The cup was evidently widely open and shallow, 

 not partially closed as it is in Q. lyrata. Fossil acorn-cups 

 have been found in the Miocene of Europe (Q. palceocerris 

 Sap., Q. subcrenata Sap.). 



Rosa ruskiniqna sp. nov. Fig. 5. 



Represented by a bud about 16 mm long, and six in 

 diameter. Hypanthium subglobose, no doubt producing a 

 practically spherical fruit, covered with minute spines; sepals 

 with very large and thick-stalked glands or gland hairs on the 

 basal half, these very much larger than the spines of the 

 hypanthium ; apical portion of sepals long, with three or four 

 large lobes on each side. 



Florissant, Station 13 B (W. P. Cockerell, 1908). By the 

 character of the hypanthium this is evidently related to Posa 

 cherokeensis Donn., but the sepals are strongly lobed. Such a 

 rose would have trifoliate leaves, and these should resemble 

 those of P. hillice Lx., at least to a considerable degree. As, 

 however, it is impossible definitely to connect the bud with 

 the leaves of P. hilliw (we have not found the latter), I give 

 the former a distinctive name ; dedicating it to John Buskin, 

 whose copy of Lindley's " Bosarum Mionographia," with many 

 marginal notes, is in my library. 



