201 



Perigynia glabrous. Carex impressa (Wright) Mackenzie. 



Specimens examined, all from the herbarium of Mr. K. K. Mackenzie. 



Indiana: Wells Co., C. C. Deam, May 22, 1908. Posey Co., C. C. Deam, May 

 23, ipir. Porter Co., C. C. Deam, June 17, Jon. 



A NEW FOSSIL SELAGINELLA FROM THE LOWER 

 TERTIARY OF MONTANA* 



By F. H. Knowlton 



The remains of lycopodiaceous plants appear to be very rare in 

 Mesozoic and later horizons, and when one is discovered that 

 shows not only the foliar organs, but the fruiting organs as well 

 in a high degree of perfection, it merits immediate description, 

 and this is the warrant for the present publication. 



The beautifully preserved specimens here described as Selagi- 

 nella were obtained during the past summer (1915) by Mr. A. J. 

 Collier, of the United States Geological Survey, in the northeast 

 Montana coal field, at a point a few miles south of the interna- 

 tional boundary, in sec. 33, T. 37 N., R. 47 E. The material in 

 which they are preserved is a white, very fine-grained clay es- 

 pecially adapted to retaining even the most delicate plant struc- 

 tures. The plants in association with the Selaginella indicate 

 that they probably grew in or very close to the body of water in 

 which they were deposited. These comprise an alga, stems and 

 roots of Equisetiim, leaves and stems of coarse sedges, a fern 

 {Onoclea sensihilis fossilis), a leaf apparently of Potamogetony 

 and a stem bearing whorls of leaves of what is known as Trapa ? 

 microphylla Lesq. The latter specimen throws much light on 

 the affinity of a plant that has long been imperfectl}^ understood. 

 It will be described and figured on a later occasion. 



The Selaginella may be known as: 



Selaginella CoUieri n. sp. 



Plate I, figures 1-6 



Stems very slender, weak, evidently erect or suberect, probably 

 from a decumbent base, about 2 centimeters high, pinnate, the 

 branches alternate, close, the lower one or two compound; leaves 



* Published with the permission of the Director of the U. S. Geological Survey. 



