108 



LAEAMIE FLOXA OF THE DENVER BASIN. 



pediceled "capsules" as the living species. 

 The living form, as is well known, has the 

 fertile pinnules rolled up into berry-like bodies, 

 on the outside of which thick veins are very 

 prominent. In the fossil this feature is appar- 

 ently absent. Considering the fact that this 

 fruiting portion has been found only once, it is 

 not strange that the sterile portion remains 

 unknown. 



A species that has a somewhat similar history 

 has been found in the Raritan and Magothy 

 formations of southern New York and the 

 islands south of the New England mainland. 

 It was first described as Caulinites inquirendum 

 Hollick 2i and later transferred to Onoclea 35 

 on the ground of its resemblance to the species 

 under consideration. Like our form, it has 

 pinnately arranged branches with the spheroi- 

 dal "capsules" in a single row on each side, and 

 associated sterile fronds have not been found 

 with it. 



One of the most abundant a*ud widely dis- 

 tributed plants of the Fort Union formation 

 is a fern that can not be distinguished from the 

 living sensitive fern, Onoclea^ sensibilis. It 

 occurs at some localities by hundreds, but in 

 only one known place in all the vast area 

 covered by the Fort Union formation has it 

 been found fruiting. In a small collection 

 obtained near Porcupine Butte, Sweetgrass 

 County, Mont., there were many of the usual 

 sterile fragments, and associated with them a 

 few fertile fronds. 38 A comparison of these 

 fertile fronds with the Laramie specimens under 

 consideration shows a close, at least generic 

 similarity. 



Thus, as at present provisionally marked 

 out, our knowledge of the geologic history of 

 the living sensitive fern may stand as follows : 



Onoclea inquirenda Hollick Raritan. 



Onoclea neo-mexicana Knowl- Montana. 



ton. 

 Onoclea fecunda (Lesquereux) Laramie. 



Knowlton. 

 Onoclea sensibilis fossilis New- Fort Union. 



berry. 

 Onoclea sensibilis Linn6 Living. 



« Hollick, Arthur, New York Bot. Gard. Bull., vol. 3, p. 40j, pi. 20,! 

 fig. 3, 1904. 



25 Hollick, Arthur, U. S. Geol. Survey Mon. 50, p. 32, jl. 1, figs. 1-7, 

 19D6. 



» Knowlton, F. H., Torrey Bot. Club Bull., vol. 29, p. 705, p. 26, figs. 

 j-4, 1902. 



Occurrence: Laramie formation, Erie, 

 Boulder County, Colo., collected by Leo Les- 

 quereux about 1872. 



Dryopteris georgei Knowlton, n. sp. 



Plate I, figures 6, 7. 

 Fronds probably of large size but the com- 

 .plete outline unknown, though apparently it 

 ' was at least thrice 'pinnatified; main rachisnot 

 sure; secondary rachis strong, straight, grooved; 

 pinnae apparently lanceolate; pinnules numer- 

 ous, very close, alternate or subopposite, 

 narrowly linear-lanceolate, sessile, narrowly 

 acuminate at apex, cut into numerous small, 

 oblong, rather obtuse lobes, the cutting being 

 made less toward the apex; nervation fairly 

 strong, consisting of a stout midvein and five 

 or six pairs of once-forked veins; fruit not 

 seen. 



This fine species, which I am able to include 

 by the courtesy of Prof. R. D. George, of the 

 University of Colorado; is all that has been 

 found, and although a considerable portion of 

 the frond is preserved it was evidently of 

 much larger size when perfect. Two of the 

 pinnae are parallel and lie in such a position 

 as to suggest that they were attached to a 

 common rachis, in which case the whole frond 

 must have been of imposing appearance. The 

 pinnae appear to have been 15 or 20 centi- 

 meters in length and 7 or 8 centimeters in 

 width. The pinnules, as already noted, are 

 narrowly linear-lanceolate, their length being 

 4 or 5 centimeters and their width about 1 

 centimeter at base; they begin to narrow near 

 the middle and become narrowly acuminate 

 at the apex. 



The coriaceous appearance of the frond and 

 its rather strict aspect suggest the probability 

 that it was «f xerophytic habit. 



The photograph showing the whole frond 

 somewhat less than natural size was sent by 

 Prof. George, who also, kindly donated the two 

 fragments of the counterpart shown in figures 

 6 and 7. . 



Occurrence: Laramie formation, shaft of 

 Columbia mine, 150 feet from the surface, near 

 Louisville- Junction, Boulder County, Colo., 

 submitted by R. D. George. Type specimen 

 in the Museum of the University of Colorado. 

 Boulder, Colo.; pieces of counterpart in United 

 States National Museum. 



