DESCRIPTION OF SPECIES. 37 



MONOCOTYLEDONES. 



Order GRAMINE^. 



Tribe FESTUCEyE. 



Subtribe AEUNDINEJ5. 



- Phragmites cretaceus Lesq. 

 PI. II, Fig. 8, 



Equisetum nodosum Lesq., Cret. aad Tert. Fl., p. 25. 



Part of rliizoma ; branch irreg'ular in thickness, partly linear and nodose; 

 articulate at unequal distances, articulations more or less inflated, marked by 

 I'ound small scars of radicles. 



As this is merely a fragment of a rhizoma related to Phragmites by its 

 unequally distant irregular articulations, marked on the upper and lower 

 side by round scars of radicles, it is not possible to define its species. For the 

 generic I'elation it is not only comparable but really very similar to P. a'nin- 

 gensis Al. Br., as figured by Heer,^ especially in the irregular length of the 

 nodes, which are somewnat inflated below the line of articulation. In this 

 branch the scars of rootlets are very irregular in position, some being above, 

 some below the articulations, exactly as they are represented in size and 

 })<)sition in Heer (loc. cit., Fig. 5a). 



This fragment was at first considered as part of a rhizoma of Equisetum; 

 but its analogy is more marked with Plu-agmites, a genus which is already 

 represented in the Dakota Group by fragments of leaves and stems ;^ hence 

 its reference to the same species, though hypothetical, seems to be authorized. 



Habitat : Seven miles northeast of Glascoe, Kansas. No. 473 of the 

 Museum of Comparative Zoology of Cambridge, Massachusetts. 



Order ALISMACE^E. 



Tribe ALISME^^. 



Alismacites dakotensis, sp. nov. 

 PI. II, Fig. 10. 



Leaves siTbcoriaceous, entire, long-petioled, elliptical, acuminate; median 

 nerve strong; secondaries, two pairs, inequidistant, cur\ang up and tending 

 to the apex at a very acute angle of divergence; simple. 



'Fl.Tert. Helv., vol. 1, PI. xxii, Figs. 5a, 5b. 



= Cret. Fl., p. 55, PI. i, Figs. 13, 14 ; PI. xxtx, Fig. 7. 



