[Horsebrush: The Genus Tebradymia East of the Cascade Mts. of Oregon and Washington]

Gray Horsebrush, Spineless Horsebrush

Tetradymia canescens

Synonym: Tetradymia inermis

Inflorescence of Gray Horsebrush: Tetradymia canescens
A close-up of the inflorescence of gray horsebrush as photographed in prairie and scabland along Wilson Creek, a BLM site several miles south of US Highway 2 in central Washington.........June 25, 2006.

Characteristics:

Gray horsebrush is a much-branched, unarmed shrub from 20 to 60 cm tall. The twigs, leaves, and flower involucres are notably white-tomentose. The leaves are linear or oblanceolate, measuring from 1-3 cm long and 1-4 mm wide. The leaf tips narrow abruptly to a narrow spine-like tip. The leaves are often closely ascending or appressed to the twig (See photo at right.). The leaves are deciduous in the autumn.

The flower heads are in small cymes at the ends of the numerous short branches, with 4 (occasionally 5) flowers in each head. The involucres are about 7-10 mm high and consist of 4 tomentose, oblong bracts.


Habitat:

Gray horsebrush is found in open, dry places in the foothills and plains.


Range:

Gray horsebrush is found from southern British Columbia east to Montana, and south through the Pacific Northwest to California, and hence eastward to New Mexico.


Involucral bracts of Gray Horsebrush: Tetradymia canescens

The photo above shows a close-up side view of the flowerheads of gray horsebrush. Note the long, narrow involucral bracts at the base of each flowerhead. Photographed in prairie and scabland along Wilson Creek, a BLM site several miles south of US Highway 2 in central Washington..........June 25, 2006.

Gray Horsebrush: Tetradymia canescens

Gray horsebrush as seen at Rimrock Lake in Moses Coulee, central Washington.......June 7, 2009.

Gray Horsebrush, Spineless Horsebrush: Tetradymia canescens (Synonym: Tetradymia inermis)

Gray Horsebrush, Spineless Horsebrush: Tetradymia canescens (Synonym: Tetradymia inermis) - Gray Horsebrush, Spineless Horsebrush: Tetradymia canescens (Synonym: Tetradymia inermis) - Gray Horsebrush, Spineless Horsebrush: Tetradymia canescens (Synonym: Tetradymia inermis)

Gray horsebrush as seen in bloom at the western base of Dry Falls Dam, Coulee City, Washington.........June 2, 2013.

Gray Horsebrush, Spineless Horsebrush: Tetradymia canescens (Synonym: Tetradymia inermis) - Gray Horsebrush, Spineless Horsebrush: Tetradymia canescens (Synonym: Tetradymia inermis)

Gray horsebrush as seen at left along the Rimrock Springs Trail #850, Crooked River National Grasslands.........June 24, 2017. The photo at right shows what might be the stem and leaves of gray horsebrush along the Alder Springs Trail #855, Crooked River National Grasslands.......May 11, 2018.

Flower heads of Gray Horsebrush: Tetradymia canescens

Tetradymia canescens found along the road to Blue Sky, Hart Mt. National Antelope Refuge........June 29, 1997.

Gray Horsebrush, Spineless Horsebrush: Tetradymia canescens (Synonym: Tetradymia inermis)

The photo above shows a side view of the inflorescence and upper stem leaves of gray horsebrush as found at Cow Lakes C.G., BLM, SE Oregon.........June 27, 1999.

Gray Horsebrush, Spineless Horsebrush: Tetradymia canescens (Synonym: Tetradymia inermis)

The photo above shows a side view of the inflorescence of gray horsebrush as found along US Highway 26 through the Warm Springs Indian Reservation.........June 26, 1997.

Paul Slichter