108 



LARAMIE FLORA OF THE DENV-ER BASIN. 



pediceled ''cnpsules" as the living species. 

 The Hving form, jis 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 f)orti()n 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 Karitan and Magothy 

 formations of southern New York and the 

 islaiuls south of the New England mainland. 

 It was first described as CauUnites Inquireiidus 

 Hollick " and later transferred to Onoclea ^' 

 on the ground of its resemblance to the species 

 under consiileration. Like our form, it has 

 pinnately arranged branches vnth 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 and widely dis- 

 tributed plants of the Fort Union formation 

 is a fern that can not be distinguished from the 

 living sensitive fern, Oitocha seuftihUh. 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.'" 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-mexioana Knowl- Montana. 



ton. 

 Onoclea fecuncia ( Lesquereuxj Laramie. 



Knowllon. 

 Onoclea sensibilis fossilis New- Fort Union. 



berry. 

 Onoclea sensibilis Linn6 Living. 



'< Holli k. .\rthur, New York Hot. Card. Bull., vol. 3, p. 4^', pi. 2ti, 

 fig. 3, 1«H. 



■iHnlUck, Arthur, V. S. Ceol. Suricy Mon. 50, p. :i2, [1. 1, lig;. 1-7, 

 19D(i. 



» Knowllon, F. II.. Torrey Hot. ( liib liull., vol. a>.i, p. 70.1, p. 2il, figs. 

 1-4. 11)02. 



Occurrence: Laramie formation, Erie, 

 Boulder County, Colo., collected by Leo Les- 

 ciuereux about 1872. 



Dryopteris georgei Knowlton, n. sp. 



Plate 1, figures 6, 7. 

 Fronds probably of large size but the com- 

 plete outline unknown, though apparently it 

 was at least tlirice pinnatified; nuiin rachis not 

 sure; secondary rachis strong, straight, grooved; 

 pinnae apparenth- 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 mid vein and five 

 or si.x 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 

 L^niversity of Colorado, is all that has been 

 found, aiui although a considerable portion of 

 the frond is preserved it was evidently of 

 mucli 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 stric-t aspect suggest the probability 

 that it was of xerophytic habit. 



The photograph showing the whole frond 

 somewhat less than natural size was sent bj- 

 Prof. George, who also kindly donatcii 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 K. D. George. Type specimen 

 in tlic Museum of the LTniversity of Colorado. 

 Boulder, Colo.; pieces of counterpart in United 

 States National Museum. 



