Eriogonum microthecum (Nutt.) var. laxiflorum Hook.
Viridiplantae > Streptophyta > Streptophytina > Embryophyta > Tracheophyta > Euphyllophyta > Spermatophyta > Magnoliopsida > Mesangiospermae > eudicotyledons > Gunneridae > Pentapetalae > Caryophyllales > Polygonaceae > Eriogonoideae > Eriogoneae > Eriogonum > Eriogonum microthecum Nutt. > Eriogonum microthecum var. laxiflorum [1]
![A closer look of slender buckwheat’s inflorescence and flowers [2].](/crfs/images/native-plants/plant-directory/slenderbuckwheat-first.jpg)
A closer look of slender buckwheat’s inflorescence and flowers [2].
Shrubs that are mostly 1-5 dm tall [3] and clump forming. Branches are ascending to spreading and glabrous (smooth or maybe glossy) to tomentose (loosely covered with down or matted hair). Leaves 4-35 mm long and 1-7 mm wide, elliptic to linear or oblanceolate in shape; blades can be tomentose on one or both sides [4]; margins flat and not revolute (rolled backwards). Petioles 1-5 mm long [4]. Inflorescence cymose (grouped with a flower at the apex of the flower axis), compact, and sometimes flat topped [3] with involucres (a collection of bracts subtending a flower) that are sessile to short-stipitate, obconic (shaped like inverted cone), 2-35 mm long, tomentose or glabrous, with 5 blunt to rounded teeth. Flowers white or a saturated pink, 2-3.2 mm long, glabrous and obovate (egg-shaped) [4,5]. Fruits achenes, 2-3 mm long [4]. Seeds minute [6].
![A slender buckwheat plant in Great Basin National Park [7].](/crfs/images/native-plants/plant-directory/slenderbuckwheat-sec.jpg)
A slender buckwheat plant in Great Basin National Park [7].
Eriogonum microthecum has a number of recognized varieties, with either two or four recognized in Utah. The other three varieties are var. lapidicola which have somewhat brownish or reddish tomentum, var. phoeniceum is a sub-shrub that only grows up to 4 cm and has revolute margins, and var. simpsonii is the more woody variety of the four that grows to 15 dm in height. All of these entities are transitional and may be hard to distinguish. The traits that may aid in identifying E. microthecum var. laxiflorum include the shrub's height of 1-5 dm tall, the margins which are not revolute, and the plant bearing white tomentose rather than brown or red hairs [3]. Eriogonum microthecum as a species can have yellow-flowered forms, however, they do not occur in Utah [3].
A complex web of differing opinions and efforts by botanists over the years have resulted in numerous taxa recognized at the varietal or subspecific levels under the species Eriogonum microthecum. Eriogonum microthecum var. laxiflorum is just one. Thomas Nuttall collected this taxon over several locations during his explorations of the American West from 1834-1835, journeying from Idaho to the Oregon Coast. To add to the confusion, the exact locality where the plant was first collected and described was not recorded in great detail, leaving the type locality uncertain. Several botanists made efforts to decode Nuttall’s route and name the entity, including Bentham and Hooker, who independently gave it the same name based on the same type, resulting in different authorities being applied. Ultimately, we accept Hooker as the author of the taxon name, being the first to publish it, even if he was doing so based on Bentham’s descriptions [8].
![Close up of the white tomentum of E. microthecum var. laxiflorum leaves [9].](/crfs/images/native-plants/plant-directory/slenderbuckwheat-third.jpg)
Close up of the white tomentum of E. microthecum var. laxiflorum leaves [9].
There have not been many economic or ethnobotanical uses for slender buckwheat. There are only a few ways the plant was used for medicinal purposes by Native American tribes. There is record of the Havasupai tribe using it to make tea [10]. While some Paiute tribes would use a decoction of the plant's root or tops for tuberculosis, the stems and leaves for bladder trouble, and the whole plant in a hot compress to use as a wash for lameness or rheumatism. The Shoshoni tribe would also create these decoctions in order to treat those same illnesses and symptoms [11].
![County level range map of Eriogonum microthecum (at species level) [12].](/crfs/images/native-plants/plant-directory/slenderbuckwheat-fourth.jpg)
County level range map of Eriogonum microthecum (at species level) [12].
This variety of slender buckwheat is considered an apparently secure variety. It is not endangered and no current conservation efforts are being made currently [13].
Eriogonum microthecum var. laxiflorum is found in salt and mixed desert shrub, sagebrush, pinyon-juniper, ponderosa pine, mountain brush, and white fir communities located at 1125 to 2900 meters. Occurrences of this variety include Beaver, Box Elder, Dagget, Iron, Juab, Kane, Millard, Piute, Rich, Salt Lake, Sevier, Tooele, Uintah, and Utah counties [4]. This variety is the primary host plant for the rare Mattoni blue butterfly (Euphilotes rita mattoni) [5]. Eriogonum microthecum, as a species, can flourish in a variety of habitats, but it is frequently found in dry, sunny environments, including desert and arid plains, low mountain slopes, and shrubland. It is commonly found in pinyon-juniper desert woodlands, amidst mountain brush and in sagebrush steppe-land and is widely distributed and abundant throughout Utah National monuments and parks [6].
[1] Schoch CL, et al. NCBI Taxonomy: a comprehensive update on curation, resources and tools. Database (Oxford). 2020: baaa062. PubMed: 32761142 PMC: PMC7408187.
[2] Matson, S. (2011). Eriogonum microthecum var. laxiflorum. photograph, Long Valley, McGee Creek trailhead (Mono County, California, US). https://calphotos.berkeley.edu/cgi/img_query?enlarge=0000+0000+0911+1172
[3] Buren, R. V. (2011). In Woody Plants of Utah a field guide with identification keys to native and naturalized trees, shrubs, cacti, and vines (pp. 283–284). Utah State University Press.
[4] Welsh, S. L., Atwood, N. D., Goodrich, S., & Higgins, L. C. (2018). A Utah flora (5th, revised 2015 ed.). Marcus E. Jones Endowment Fund Monte L. Bean Life Science Museum Stanley L. Welsh Herbarium Brigham Young University.
[5] Reveal, J. L. (2022, October 27). Eriogonum microtheca var. Laxiflorum. Eriogonum microtheca var. laxiflorum - FNA. http://floranorthamerica.org/Eriogonum_microtheca_var._laxiflorum
[6] Clark, D. J. (2021). Wildflowers of Utah’s Colorado Plateau: A field guide to wildflowers of Capitol Reef National Park and surrounding areas of Southern Utah. Trails Books, an imprint of Bower House.
[7] Doyen, J. (2013). Eriogonum microthecum var. laxiflorum Slender Buckwheat. photograph, Great Basin National Park, Wheeler Peak Scenic Drive, 8000-8500’ (White Pine Co. County, Nevada, US). https://calphotos.berkeley.edu/cgi/img_query?enlarge=0000+0000+0114+1096
[8] Reveal, James L. (1971) "Notes on Eriogonum - VI : a revision of the Eriogonum microthecum complex (Polygonaceae)," Brigham Young University Science Bulletin, Biological Series: Vol. 13: No. 1, Article 1 https://scholarsarchive.byu.edu/byuscib/vol13/iss1/1
[9] Matson , S. (2011). Eriogonum microthecum var. laxiflorum. photograph, Long Valley, McGee Creek trailhead (Mono County, California, US). https://www.calflora.org/entry/occdetail.html?seq_num=mu13755
[10] Weber, Steven A. and P. David Seaman, 1985, Havasupai Habitat: A. F. Whiting's Ethnography of a Traditional Indian Culture, Tucson. The University of Arizona Press, page 217
[11] Train, Percy, James R. Henrichs and W. Andrew Archer, 1941, Medicinal Uses of Plants by Indian Tribes of Nevada, Washington DC. U.S. Department of Agriculture, page 72
[12] Eriogonum microthecum Nutt. var. laxiflorum Hook. USDA plants database. (n.d.-b). https://plants.usda.gov/home/plantProfile?symbol=ERMIL2
[13] Eriogonum microtheca var. laxiflorum Slender Buckwheat. NatureServe Explorer 2.0. (2023a, December 1). https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.152810/Eriogonum_microtheca_var_laxiflorum
