PAMMEL — NOTES ON GRASSES OF NEBRASKA, ETC. 237 



vicinity of Big Horn, a steep incline occurs. At the edge of this tim- 

 bered area some sub-arctic plants occur and a very large percentage 

 of these species are boreal. As an instance, Piniis flexilis may be 

 cited. In Northern Colorado this forms a distinct zone between 

 10,000 to 11,000 feet, but in Sheridan County it occurs at about 6,000 

 feet. 



WEEDY GRASSES OF THIS REGION. 



There are few weedy species. The most common weedy grass is 

 Squirrel-tail grass. Two species occur; the weedy species of Nebraska 

 is Hordeiim jiibatum which, as elsewhere, especially east of the Mis- 

 souri, comes up in great quantities. In South Dakota, in the vicinity 

 of Edgemont, and in Wyoming, about New Castle, Gillette, and Sher- 

 idan, the prevailing species is H. caespitosiim, although H. jicbatum is 

 not absent. It is evidently a species well adapted to dry situations 

 but grows more luxuriantly along irrigation ditches. The ever-com- 

 mon Foxtails {Chaetochloa glauca and C. znridis) are abundant in 

 Nebraska. The Hordeum pusilluin is an injurious intruder in 

 Nebraska. 



• LIST OF GRASSES COLLECTED. 



PANICE.'E.* 



Paniciirn atlmiticiim Nash. Open prairies. No. 168. Hastings, ahitude 

 '.943- 



P. capillare Linn. Broken Bow, altitude 2,478. Everywhere in fields. 

 No. 168. 



P. Crus-galli Linn. Hastings, altitude 1,943. Low grounds, common. 

 No. 22. 



P. Scribneriamun Nash. Alma, altitude 1,950. Open prairies, common. 

 No. 23. 



Chaetochloa viridis Scribner. Broken Bow, altitude 2,478. A common 

 weed everywhere in fields. No. 74. At Grand Island, everywhere a com- 

 mon weed in fields, along railroads and in streets. No. 18. It was com- 

 monly observed at other points, Alma, Aurora, and Ravenna. 



Cenchrus tribuloides Linn. Broken Bow, altitude 2,450. Sandy soil, com- 

 mon in streets and sandy flood plains of streams. No. 151. Commonly, 

 also, observed at Grand Island. 



*The numbers following the locality refer to distribution of plants of Nebraska, South 

 Dakota, and Wyoming. Distributed by the Iowa State College of Agriculture and Mechanic 

 Arts. 



[Proc. D. A. N. S., Vol. VII.] 29 [May 3, 1899.] 



