494 SMITHSONIAN AIISCELLANUOUS COLLECTIONS VOL. 52 



son to Davallia (Stenoloriia) tcniiifolia Swartz (now called Odonto- 

 soria chinensis (L.) J. Smith), a living species widely spread over 

 Japan, China, tropical Asia, Polynesia, and Madagascar. .V careful 

 comparison of the sori, which are often in an admirable state of 

 preservation, shows, however, that it is not congeneric with the 

 forms now placed in Odontosoria, but is distinctly so with the species 

 of Dennstsedtia. 



In 1883 Lesquereux' described and figured sterile portions of this 

 fern from Fort Union beds at Gilmore Station, supposed to be in 

 North Dakota,* under the name of Asplenium tencrum, apparently 

 not connecting it with the fragments previously referred by Dawson, 

 as set forth above, to Davallia teniiifolia Swartz. In transferring 

 this material to the genus Dennstaedtia, which the fruit characters 

 now enable us to do, Lesquereux's specific name if valid should be 

 the one available for the species, but unfortunately it has never had 

 nomenclatorial standing, being antedated nearly a hundred years by 

 Asplenium tenerum Forster,^ a living species, and moreover this 

 combination has been twice employed for different living forms be- 

 tween its use by Forster and Lesquereux, namely, Raddi, 1819, and 

 Gaudichaud-Beaupre, 1827. It becomes necessary, therefore, to re- 

 name it, and I have called it Dciinstcedtia ainericana. 



Although Lesquereux did not possess fruiting material of this 

 fern, he evidently had a pretty clear idea as to its relationship, for 

 he says : "Its nearest affinity is with living species of Asplenimn of 

 the section of the Dicksonicc, like Dicksonia tenera, etc." Modern 

 study of the ferns has resulted in drawing sharper generic lines, and 

 not only has Asplenium, but what was long accepted as Dicksonia, 

 been segregated into a number of smaller genera, such as Denn- 

 staedtia, Odontosoria, etc. 



So far as I know there are no fossil ferns described in this coun- 

 try that are likely to be confused with the one under consideration, 

 though, as both Dawson and Lesquereux pointed out, it is probable 



'Rept. U. S. Geo). Surv. Terr., vol. 8 (Crct. & Tcrt. Fl.), 188.^, p. 221. pi. 

 xlvi-A, figs. I, 2. 



* The full locality is given as "Bad Lands near Gilmore Station of the U. P. 

 R. R. Collected by Professor Wm. Denton." I have not been able to identify 

 exactly this locality, but it is reasonably certain that "U. P. R. R." is an error 

 for N. P. R. R., since Professor Denton is known to liaxc collected in the 

 Bad Lands of North Dakota, and possibly adjacent Montana, through which 

 runs the Northern Pacific railroad. Moreover, this species has since been col- 

 lected at a number of places in North Dakota. 



* Flor. Tns. austral. Pmd., 1786, p So. 



