34 Muhlenbergia, Volume 9 
The references to Washington, Bennett and Washabaugh 
counties are based on a collection made in 1911, determined by 
Dr. P. A. Rydberg, of the New York Botanical Garden. Fora 
full list see Bulletin 5, South Dakota Geological Survey, No- 
vember, 1912. The Harding county collections were deter- 
mined by Aven Nelson. For a complete list see Bulletin 7 of 
the South Dakota Geological Survey, 1913. 
EQUISETUM FLUVIATILE L.? Horsetail. 
Tolerably common along streams; (Minnesota valley). 
AGROPYRON OCCIDENTALE Scribn. Wheat grass. 
Common along streams. Reported in 1894 as A. repens 
glaucum by Rydberg, but given only from eastern South Da- 
kota by Saunders. 
AGROSTIS ALBA L,. 
Plentiful on stream margins throughout the foothills. 
Though Rydberg recorded it from the Hills, Saunder’s Catalog 
mentions it only from an extreme eastern locality. 
AGROSTIS ASPERIFOLIA Trin. 
Common along streams. Reported under 4. exarata by 
Rydberg as rare near Hot Springs. 
Bromus Richardsonit Link. ‘Wild oats” 
Rare along some of the valleys of the foothills. Not be- 
lieved by Rydberg to be distinct from 2. czlatus. 
CALAMAGROSTIS MONTANENSIS Scribn. 
Locally abundant along streams; (Jaines and Sioux valleys). 
Muhlenbergia comata (Thurb.) Benth. Dropseed. 
Abundant on foothills. 
Puccinelhia airoides (Nutt.) Wats. & Coult. 
Plentiful in valleys. 
Sttanion Hystrix (Nutt.) J. G. Smith. 
Rare on the foothills near Edgemont. 
Sporobolus brevifolius (Nutt.) Seribn., 
Abundant along all streams. Also collected in Washing- 
ton county. 
