THE FLORA. 



109 



Dryopteris laramiensis Knowlton. 

 Plate I, figure 5 (type). 



Dryopteris laramiensis Knowlton, U. S. Geol. Survey- 

 Bull. 696, p. 248, 1919. 



Lastrea (Goniopteris) intermedia Lesquereux, Tertiary flora: 

 U. S. Geol. Survey Terr. Rept., vol. 7, p. 56, pi. 

 4, fig. 14, 1878. [Lesquereux's original figure is 

 here reproduced.] 



Aspidium (Lastrea) pulchellumt Heer, or A. fischerif 

 Heer. Lesquereux, U. S. Geol. and Geog. Survey 

 Terr. Ann. Rept. for 1870, p. 384, 1872. 



This species is evidently very closely related 

 to Dryopteris lesquereuxii, from which it appears 

 to differ in having the pinnae closer, at a more 

 acute angle of insertion on the rachis, and with 

 the pinnules or lobes somewhat longer. 

 Neither of these differences is of much impor- 

 tance, and it is quite possible that a series of 

 specimens, if they were available, would show 

 the two forms as merging, but so far as known 

 the specimen figured by Lesquereux is the 

 only specimen extant, and if it were not for 

 some phases of the earlier history of the present 

 "species," it would perhaps do no great harm 

 to combine them. The N specimens on which 

 Lesquereux founded Lastrea intermedia are 

 involved in some complications. In the first 

 mention " s (under the designation Aspidium 

 pulchellum Heer, or A. fischeri Heer) they are 

 said by Lesquereux to have come from "Muddy 

 Creek," without mention of the State or other 

 more exact location. From Hayden's itiner- 

 ary, which precedes the report on the fossil 

 plants, it appears reasonably certain that they 

 must have come from the Muddy Creek that 

 rises in Bridgers Pass, in the mountains south 

 of Rawlins, in Carbon County, Wyo., and flows 

 into Little Snake River. At a point in the 

 valley of this stream near Barrel Springs 

 Hayden 2S found, in addition to shells, remains 

 of turtles, fish, etc., "a few obscure plants, 

 like blades of grass, stems of rushes, etc., in 

 the, clays; still higher up on the tops of the 

 hills that border the stream are some thin, 

 chalky clays crowded full of plants, as ferns, 

 rushes, grasses, palms, etc., finely preserved." 

 It is doubtful if any of this material is present 

 in the collections of the United States National 

 Museum, at least under this designation. 



In the next mention of Lastrea intermedia 

 by Lesquereux 29 it is said to have come from 



" U. S. Geol. and Geog. Survey Terr. Ann. Rept. for 1870, p. 384, 1872. 



" Idem, p. 73. 



» The Tertiary flora: TJ. S. Geol. Survey Terr. Rept., vol. 7, p. 56, 1878 



85344—22 8 



"Henrys Fork, a mixed lot." It is easy to see 

 how this mistake arose, for in the Annual Re- 

 port for 1870, page 384, the designation 

 "Henrys Fork" occurs at the top of the page, 

 while that of "Muddy Creek" is in the middle 

 of the page without indention or other display 

 and so is easily overlooked. But this error is 

 apparently responsible for Lesquereux's refer- 

 ence of Lastrea intermedia to the Green River 

 formation, 30 which would doubtless be correct 

 if it had actually come from Henrys Fork. 

 There seems, therefore, absolutely no warrant 

 for Henrys Fork as a locality or Green River 

 formation as a horizon for this species. 



Golden, Colo., is also given by Lesquereux 31 

 as a locality for "Lastrea intermedia/' and the 

 only specimen figured is preserved in the 

 United States National Museum. It is pre- 

 served on the hard white sandstone character- 

 istic of the Laramie at this locality and is ap-^ 

 parently correctly recorded. 



Owing to the absence of all specimens, except 

 the oneifrom the Laramie at Golden, the occur- 

 rence of this form in Wyoming will have to be 

 ignored, at least until more material has been 

 procured. 



Occurrence: Laramie formation, Golden, 

 Colo. 



Dryopteris lesquereuxii Knowlton. 



Aspidium goldianum Lesquereux, 32 U. S. Geol. and Geog. 



Survey Terr. Ann. Rept. for 1873, p. 393, 1874. 

 Lastrea (Goniopteris) goldiana Lesquereux, Tertiary flora: 



U. S. Geol. Survey Terr. Rept., vol. 7, p. 56, pi. 4, 



fig. 13, 1878. 

 Dryopteris lesquereuxii Knowlton, U. S. Geol. Survey 



Bull. 696, p. 248, 1919. 



Frond bipinnate (tripinnate?), broadly del- 

 toid in outline; pinnae linear, alternate, parallel, 

 at an obtuse or rarely somewhat acute angle of 

 divergence (40°-50°), alternately and equally 

 pinnately lobed; lobes cut or separated by two- 

 thirds or three-fourths of their length, oblong- 

 lanceolate, obtusely pointed, inclined outside; 

 middle nerve strong, distinct, lateral veins five 

 to seven pairs, curving slightly upward, simple, 

 parallel. 



The ferns first described by Lesquereux 

 under the name Aspidium goldianum appear 



so The Cretaceous and Tertiary floras: U. S. Geol. Survey Terr. Rept., 

 vol. 8, p. 138, 1883. 



si Op. cit. (Tertiary flora), p. 57, pi. 4, fig. 14. 



32 This name was preoccupied by the living Aspidium goldianum 

 Hooker, 1824, now Dryopteris goldiana (Hooker) A. Gray, 1848. I have 

 therefore given the fossil orm a new name in honor of its describer. 



