DESCRIPTIONS 



Family POLYPODIACE^ 



Genus ASPLENIUM Linn6 



Asplenium? coloradense Knowlton 



(Plate 1, Figs. 1, 2) 



Asplenium? coloradejise Knowlton, U. S. Geol. Surv. Prof. Paper 101, 24.5, pl. 30, figs. 1, 2, 1917. 

 Asplenium magnum Knowlton. IloIIick, Torreya, vol. 2, 146, pl. 4, figs. 1, 2, 1902. 

 Asplenium martini ICnowIton, U. S. Geol. Surv. Prof. Paper 130, 111, pl. 2, fig. 6, 1922. 



Two well-preserved specimens and one fragmcnt are clearlyidentical with the figured and type 

 specimens of Asplenium? coloradense Knowlton from the Vermejo formation of Colorado. Thc 

 shape and disposition of the pinnules are precisely as in Knowlton's figure 2, and the vcnation is 

 the same, consisting of about eight or nine pairs of veins which fork once just above the midvcin. 



Knowlton has previously included in this species the specimens from Rockvale, Colorado 

 which Hollick had regarded as Asplenium magnum Knowlton. This seems clearly justifiable. 

 It is not possible, moreover, to distinguish this species from Asplenium. martini Knowlton from the 

 Laramie of Colorado. Although pointing out its close relationship, Knowlton maintaincd this as 

 a separate species on the basis of "its larger size, more obtuse pinnules, and much stronger vena- 

 tion." 1 In view of the variation shown in the shapes of the pinnules of Aspleniumf coloradense 

 Knowlton, with those near the base being larger and more obtuse than the rest, and the identity 

 of tlie venation, it seems impossible not to inchide all of these specimens in the single species 

 which has priority. The generic reference is still open to question, pending the discovery of at- 

 tached fructifications. 



Occurrence — Corson Ranch, Wyoming, Loc. P. 371. 



Colledion—V. C. Mus. Pal., Plesiotypes Nos. 1289, 1394. 



Genus DRYOPTERIS Andanson 

 Dryopteris? carbonensis Knowlton 

 (Plate 1, Figs. 3-7) 

 Dryopterisf carhmensis I&owlton, U. S. Geol. Surv. Prof. Paper 130, 110, pl. 20, figs. 3-5, 1922. 



This form is represented by seven specimens, five of which are figured. Most of the speci- 

 mens are fragmentary or poorly preserved. The general form, size, and disposition of tlie pinnules, 

 however, is adequately shown in figure 6; details of tlie venation appear in figure 7. 



In all observable features these specimens are indistinguishable from the figures and type 

 specimens of this Laramie species. The details of the venation are somewhat better preserved 

 than in Knowlton's specimens, indicating, as he intimated, that some of the finer veins are once- 

 forked near the midvein. 



Knowlton has previously recorded ^ the presence of this species in the Medicine Bow forma- 

 tion in a manuscript Ust based on coUections at the U. S. National Museum. Unclassified speci- 

 mens (Nos. 590, a, h, c, e) of similar pinnules have been identified in the coUections from Black 

 Buttes, Wyoming, which I have consulted at the U. S. National Museum. 



There is no positive evidence for the reference of this species to the genus Dryopteris, except 

 a general resemblance in shape, size, and venation of pinnules. A more definite allocation cannot 

 be made without better material and associated fertile fronds. 



Occurrence — Corson Ranch, Wyoming, Loc. P. 371. 



Collection—V. C. Mus. Pal., Plesiotypes Nos. 1290, 1291, 1395, 1396, 1397. 



'Knowlton, F. H., U. S. Geol. Surv. Prof. Paper 130, 111, 1922. 

 «Knowlton, F. H., U. S. Geol. Surv. Bull. 696, 752, 1919. 



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