[Horsetails East of the Cascade Mountains of Oregon and Washington]

Smooth scouring-rush as seen in moist soils along the road through Ochoco Forest Camp, Ochoco National Forest........May 29, 2016.

The photo above shows the black-tipped teeth atop a sheath of smooth scouring-rush as seen in moist soils along an irrigation canal along the Willard Springs Trail at Conboy Lake National Wildlife Refuge..........July 28, 2006. The sheaths at each joint do not have a black band below the teeth as in some other horsetails. Note also that the number of teeth is the same as the number of ribs at the sheath.

Smooth scouring-rush as seen in a dry stream bed meandering across prairie adjacent to Lakeside Rd in Conboy Lake NWR.........August 10, 2007. Note that the sheaths are banded with black only along the upper edge.

Smooth scouring-rush as seen in a meandering stream in the middle of Swampy Meadows at the southwest corner of Mt. Adams...........August 8, 2004.