 | | Mature Roundleaf Buffaloberry, Zion National Park, Utah |  |
Roundleaf Buffaloberry
Shepherdia rotundifolia Parry 1875
C. Michael Hogan PhD
December 1, 2009
Roundleaf Buffaloberry is a moderately abundant shrub of the Great Basin and Colorado Plateau, with occurrences along desert washes and rocky slopes. The genus name honors English botanist John Shepherd. Species biomass density has been declining since the mid-Holocene, likely due to grazing land conversion for livestock. Many medicinal and ceremonial prehistoric uses of this plant are documented. The berries serve as a food source for a variety of wildlife species.
DISTRIBUTION
S. rotundifolia occurs in northern Arizona, north of the Mogollon Rim. In Utah the species is found distributed across the southern portion of the state.(Lamb) S. rotundifolia is also found in portions of central Nevada. (Silliman) Specific places in Arizona that I have observed this shrub are: Monument Valley, Grand Canyon National Park, Navajo National Monument and Kaibab National Forest. Arizona counties of occurrence are Navajo, Parry, Coconino, as well as the eastern part of Mojave County. Locales I have seen the species in Utah include: Zion National Park, Bryce Canyon National Park, Kodachome State Park, Canyonlands National Park, Dead Horse Point State Park, Hovenweep National Monument, Escalante Grand Staircase National Monument and Capitol Reef National Park. Although not noted in most distribution reports, I have observed this taxon in the extreme western part of Colorado, at the Holly Unit of Hovenweep, Canyon of the Ancients. Elevations of occurrence range from 1500 to 2400 meters.
The nineteenth century type location was established as the upper Virgin River Valley on bare clay soils. (California Academy of Sciences) Other early collection sites of the taxon were given as moist benches beneath cliffs near Bluff City, Utah near the San Juan River, and in the headwaters area of Willow Creek, a tributary of Green River.
MORPHOLOGY
 | | Close-up of main branching stem, Roundleaf Buffaloberry, Zion National Park, Utah | |
Roundleaf Buffaloberry is a small to medium sized densely branched evergreen shrub, that may take on a sprawling growth habit.(Van Dersal) Mature height is typically 90 to 200 cm. The opposite roundish leaves are approximately 1.5 to 2.2 cm, (Epple) with leaf margins being smooth and leaf apex slightly rounded; (Franklin) moreover, the convex leaves are a silvery gray-green above and yellowish-white woolly or scaly beneath. Blooms manifest as clusters of small, bell-shaped yellowish-tan flowers. Flowering occurs in March through June, and the fruit is a sweet juicy berry yielding yellow liquid.(Kearney and Pebbles)
Diagnostic features distinguishing S. rotundifolia from other genus members include persistent winter foliage, absence of thorns, nearly globose fruit, round-oval to sub-orbicular leaf shape and absence of tomentose texture on the leaf upper surface. S. argentea, by contrast, is deciduous and thorny, with oblong leaves cuneate at the base and fruit ovoid to ellipsoid; in addition, S. argentea may attain a substantially greater height of up to six meters. S. canadensis is deciduous, with leaves ovate to elliptic, with unpalatable ellipsoidal berries. Pollen grains of this taxon are distinct from other genus members, providing the modern day scientist a good tool for species level identification of prehistoric pollen cores. The grains of S. rotundifolia are angulaperturate (e.g. apertures at the corners of the angular amb), with the amb sides mildly convex.(Erdtman)
ECOLOGY
Roundleaf Buffaloberry typically occurs on sun drenched semi-desert sandy loam soils. (Witwiki and Biel); however, the shrub may also occur on more clay-like soils. S. rotundifolia is characteristically found on deeper loams on mesas, valleys and edges of desert valley floors In Arizona it is frequently found on moderately steep dry rocky slopes.. Often the shrub is seen near desert washes on alluvial fans at the base of desert mountain foothills, including specific incidence at Entrada Sandstone formations such as at Kodachrome State Park, Utah. In other cases the species occurs in more stony hillside areas such as Navajo Sandstone dominated areas of Canyonlands National Park. The soils associations may also include aeolian deposits derived from eroded sandstones.
Typical dominant flora associates include Utah Juniper (Juniperus osteosperma), (Hogan) Fourwing Saltbush (Atriplex canescens), Bigelow's Sagebrush (Artemisia bigelovii), Giant Sagebrush (A. Tridentata), Torrey's Mormon Tea (Ephedra torreyana), Rabbitbrush (Chrysolthamnus nauseosus), Shadscale (Atriplex confertifolia), Spiny Hopsage (Grayla spinosa), Indian Ricegrass (Oryzopsis hymenoides) and Needle and Thread Grass (Hesperostipa comata).
S. rotundifolia is consumed by a variety of birds and mammals, including Black-tailed Deer, Pale Chipmunk, Western Chipmunk and Ruffed Grouse. This shrub is regarded as a valuable livestock forage plant in southern Utah.
INTERACTION WITH MAN
Fossil and pollen records indicate that the biomass density of S. rotundifolia is at its lowest level in 5400 years. It is unknown to what extent this decline is due to prehistoric or historic human activity; however, introduction of livestock grazing by Europeans as early as the middle 1800s is a suspect cause, due to the palatability of the species. Prehistorically the Navajo and Kayenta people utilized Roundleaf Buffaloberry ash as a lotion for headaches.(Lewis and Elvin-Lewis; Moerman) Havasupai people extracted a poison dust from the leaf undersides to create an irritant that could cause blindness. The ash was also used in ceremonial Plumeway sand paintings; furthermore, some prehistoric Native Americans employed the plant ash as a toothache and sore throat remedy. In modern times the berry is used to make an edible jelly.
REFERENCES
* S. H. Lamb. 1975. Woody Plants of the Southwest: A Field Guide With Descriptive Text, Drawings, Range Maps, and Photographs, 177 pages
* Benjamin Silliman (ed.). 1879. The American journal of science and arts. page 425
* California Academy of Sciences. 1897. Proceedings of the California Academy of Sciences, page 323
* William Van Dersal. 2007. Native Woody Plants of the United States, page 260
* Scott B. Franklin. 2002. Taxonomy and ecology of woody plants in North American forests, page 353
* Lewis E. Epple. 1997. Plants of Arizona, page 169
* Thomas H. Kearney, Robert H. Pebbles. 1960. Arizona flora, page 586
* G. Erdtman. 1986. Pollen Morphology and Plant Taxonomy: Angiosperms, an introduction to palynology, page 157
* Dana Witwiki and Alice W. Biel. 2008. Integrated Upland Monitoring in Capitol Reef National Park, 2008 Annual Report. Natural Resource Technical Report NPS/NCPN/NRTR-2009/237
* C. Michael Hogan. 2009 Utah Juniper: Juniperus osteosperma, GlobalTwitcher.com, ed. N. Stromberg
* Cambridge Scientific Abstracts Inc. 1998. Ecology abstracts, page 229, Information Retrieval Limited
* Walter H. Lewis & Memory P. F. Elvin-Lewis. 2003. Medical botany: plants affecting human health, page 429
* Daniel E. Moerman. 2009. Native American Medicinal Plants: An Ethnobotanical Dictionary, page 454
|
|
