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   Purshia tridentata has an elevation range from about 1,000-2,700 meters and blooms from about April-July and is thus is a bit more widespread and has a bit longer blooming period than Purshia stansburyana which ranges from about 1,200-2,000 meters and blooms from May-June.  The two enjoy the same habitats and do have similar looking flowers and leaves.  A close look shows differences:

P. stansburyana leaves have three lobes at the apex and one more lobe on each side below the apex; P. tridentata (as its name suggests) has just three lobes, and these are at the apex only.  The leaves of P. stansburyana commonly have an odd, quinine-like odor that emanates from the white gland dots on the leaf surface. (Click to see).

The seeds of P. stansburyana are borne below long, feathery elongated styles (click to see); the seeds of P. tridentata are encased in pyramid-shaped nutlets and the mature style is neither elongated nor feathery.  Seeds of both plants are gathered in large numbers by rodents or the wind and some of these clusters sprout in the spring.  Click to see the sprouts.

The growth form of the two plants is usually quite different and tells you, even from a distance, which plant you are looking at.  Purshia tridentata is most often low, twisted, and spreading; it is typically about six feet wide and three feet high with many horizontal and even prostrate, inter-twining gray stems. Purshia stansburyana can be quite wide but it is more upright, often 5-9 feet tall with more vertical and somewhat arching stems and dark, shredded bark.

Purshia hybridAs shown at left, the two shrubs do hybridize; leaves may have the characteristic smell and white scale of P. stansburyana, the hairiness of P. tridentata, and a mix of the leaf shape, height, and width of the two.

Purshia tridentata was first collected by Meriwether Lewis on the Lewis and Clark Expedition, July 6, 1806 near Lewis and Clark Pass, Montana.  Frederick Pursh, the first to receive, work on, and publish the Lewis and Clark botanical collections, named the plant Tigarea tridentata in his 1814 publication, Flora Americae Septentrionalis, which included much of the known Lewis and Clark botanical collection.  In 1817 the plant genus name was deemed incorrect by the eminent Swiss botanist Augustin Pyramus de Candolle; he created a new genus, Purshia, and renamed the plant, Purshia tridentata.  (More biographical information about Pursh.)

Purshia stansburyana was at first named Cowania stansburyana by John Torrey in 1852, was renamed Cowania mexicana by Jepson in 1925, went through a number of other name changes, and since 1986 has retained the name Purshia stansburyana given it by Henrickson.

Purshia stansburiana

Purshia stansburiana

Purshia stansburiana

Purshia stansburiana

Purshia stansburiana

Purshia stansburyana.  Synonyms: Cowania stansburyana, Cowania mexicana.  (Cliffrose)
Rosaceae (Rose Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Canyons of the Ancients National Monument, May 11, 2016 and
Hunter Canyon, Utah, May 3, 2005.

Cliffrose is very common in the drier semi-desert areas from about 1200-2000 meters. It blooms during May and June, is almost invariably cloaked in a super abundance of blossoms, and is one of the sweetest scented of all Southwest plants.

Shredded bark branches twist and turn and are quite a contrast to the
lovely symmetry of the flowers.  During the drought years of 1999-2004,
some Cliffrose bushes and many branches died, but after the 2004-2005
winter torrents of moisture, Cliffrose bloomed in massive profusion.

"stansburyana" honors Howard Stansbury, mid-19th century surveyor,
explorer, and naturalist.   In 1850 Stansbury was the first to collect
this lovely shrub (on what is now Stansbury's Island in the Great Salt Lake)
and John Torrey honored him in the name of the plant. 
(More biographical information about Stansbury.)

Purshia stansburiana

Purshia stansburiana

Purshia stansburiana

Purshia stansburyana. Synonyms: Cowania stansburyana, Cowania mexicana.  (Cliffrose)
Rosaceae (Rose Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Hunter Canyon, Utah, May 3, 2005.  Canyons of the Ancients National Monument, May 29, 2013.

Cascades of flowering branches are  the rule, not the exception for Cliffrose, and this majesty makes the plant a favorite of many people.

A myriad of flowers is preceded by a myriad of spherical buds and is followed by a myriad of feathered seeds, the elongated styles. Such seed-bearing plumes are found on a number of plants in the Southwest. See Cercocarpus montanus and Fallugia paradoxa for two other prominent examples.

Purshia stansburiana

Purshia stansburiana

Purshia stansburyana.  Synonyms: Cowania stansburyana, Cowania mexicana.  (Cliffrose)
Rosaceae (Rose Family)  

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.  Canyons of the Ancients National Monument, May 25, 2010 and
Canyonlands National Park, Confluence Trail, May 20, 2004.

Purshia stansburiana

Purshia stansburiana

Purshia stansburiana

Purshia stansburyana.  Synonyms: Cowania stansburyana, Cowania mexicana.  (Cliffrose)
Rosaceae (Rose Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Canyons of the Ancients National Monument, May 25, 2010 and Behind the Rocks Wilderness Study Area, Utah, April 14, 2009.

The tiny, five-lobed, leathery leaves of Cliffrose have minute glandular dots  and an acrid, quinine-like smell. 

In many high desert areas Cliffrose green leaves remain on the shrub year-round, although there may be some leaf drop or some yellow or red (see below). In other areas leaf drop or color change can be more pronounced. 

Notice the numerous spring flower buds in the middle photo.

Purshia stansburiana

Purshia stansburiana

Purshia stansburyana (Cliffrose)
Rosaceae (Rose Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Canyons of the Ancients National Monument, September 17, 2010 and August 9, 2016.

Feathery growth of the styles atop the seeds will carry seeds on the winds, very commonly depositing them in fluff piles at the base of Purshia stansburyana or in a nearby depression, as shown at left. You can see a number of brown seeds pointing upward out of the feathery fluff.

Purshia stansburiana

Purshia stansburiana

Purshia stansburyana (Cliffrose)
Rosaceae (Rose Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Hovenweep National Monument, June 5, 2022 and February 9, 2015.

Though 2021 and 2022 were severe drought years, Cliffroses in the Hovenweep area had a magnificent flowering followed by massive seed production. The glow in the top photograph above is from the myriad of plumose styles.

After summer growth, Purshia stansburyana may retain its green leaves, may drop some or most leaves, and/or may show leaf color change to yellow or shades of red and brown.

 

Purshia tridentata
Purshia tridentata
Purshia tridentata var. tridentata (Buckbrush, Bitterbrush)
Rosaceae (Rose Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Above: Canyons of the Ancients National Monument, May 5, 2012.
Left: Head of Hovenweep Canyon, May 8, 2006.

Purshia tridentata is as common and as fragrant as Purshia stansburyana.  It blooms from about April to July at elevations ranging from about 1,000-2,700 meters.  In its sprawling, unkempt manner, it lines long sections of road in Mesa Verde National Park and is found in abundance in many other open and forested areas of the Four Corners. 

The Purshia tridentata pictured at left is typical at six feet wide and a bit over three feet tall.  (About half of the width of the shrub shows in the photograph.)  Purshia tridentata's flowers, as those of P. stansburyana, appear to be yellow because of the abundance of yellow pollen.  The petals are white to creamy white to light yellow.  The flowers of both are intensely, wonderfully sweet smelling.  

Purshia tridentataPurshia tridentata
Purshia tridentata var. tridentata (Buckbrush, Bitterbrush)
Rosaceae (Rose Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Yellow Jacket Canyon, April 21, 2009 and Head of Hovenweep Canyon, May 8, 2006, Abajo Mountains, Utah, June 12, 2009.

Notice the three-lobed leaves ("tridentata").  At far left the silvery glow on the back side of the young leaves and outlining the front side is due to an abundance of hairs. Petals in the farthest right photograph are very pale yellow; petals can also be white. 

The above characteristics help separate the two Purshia species, but the difference in the two is even more obvious when they go to seed, for the seed capsules of P. tridentata do not have the long, feathery styles that are so attention grabbing on Purshia stansburyana.

Purshia tridentata
Purshia tridentata var. tridentata (Buckbrush, Bitterbrush)
Rosaceae (Rose Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Head of Hovenweep Canyon, May 8, 2006.

Purshia tridentata

Such clusters of sprouting plants mystified Betty and me (and our botanizing friends) for a number of years.  We finally found some plants with more than cotyledons and more than their very first leaves which usually were narrow and somewhat sharply lobed.  When more leaves came on we saw the characteristic leaf shape of Purshia tridentata.  We also found that Purshia stansburyana produced the same bean sprout-like clusters.

Few of the sprouts survive.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Purshia stansburyana

Range map for Purshia tridentata