Rvdberg : Rocky Mountain flora 599 



This is quite distinct from 5. simplex L. To the characters given 

 by the late Dr. Morong may be added the broad scarious margins 

 of the leaf-sheaths. This character it has in common with 5". ameri- 

 canum Nutt. of the eastern United States and 5. subvagmatum 

 Meinsh. of Europe. In fact, Meinshausen included C. C. Parry's 

 plant from Colorado in the latter. It is, however, very doubtful 

 if it belong there, for the original description of 5. subvaginatum 

 does not fit our plant very well. S. multipedunculatum ranges 

 from the Mackenzie River and Washington to Colorado. 



Potamogeton Richardsonii (Bennett) Rydb. 



Potamogeton perfoliatus lanceolatus Robbins, in A. Gray, Man. ed. 



5. 488. 1867. Not P. perfoliatus lanceolatus Blytt. 1861. 

 Potamogeton perfoliatus Richardsonii Bennett, Jour. Bot. 27: 25. 



1889. 



Our common North American plant does not seem to inter- 

 grade at all with the true P. perfoliatus L. 



Stipa Porteri Rydb. 



Stipa mongolica (Thurber, in A. Gray, Proc. Acad. Phila. 1863 : 

 79, hyponym. 1 863.) Port. & Coult. Syn. Fl. Colo. 145. 

 1874. Not .S". mongolica Turcz. 



In the enumeration of Hall and Harbour's plants, Thurber 

 determined this plant as 5". mongolica Turcz., which is evidently 

 erroneous. He gives the name and a short discussion but no de- 

 scription. A good description was afterwards given by Porter 

 and Coulter in the Synopsis of the Flora of Colorado. 



Muhlenbergia cuspidata (Torr.) Rydb. 



Vilfa cuspidata Torr. ; Hook. Fl. Bor. Am. 2 : 238. 1839. 

 Spo-obolus cuspidata Wood, Bot. & Fl. 385. 1870. 



The group of grasses, which Torrey, Trinius and Thurber re- 

 garded as a good generic type and for which they adopted the 

 name Vilfa, is altogether out of place in the genus Sporobolus, 

 where its species have been placed by authors. They are no 

 "Drop-seed" grasses at all, the grain remaining enclosed in the 

 firm flowering glume. They should be taken out of Sporobolus, 

 but if they should constitute a genus by themselves is question- 



