Eriogonum viridulum
Author: Reveal

Clay hill buckwheat

Polygonaceae (Buckwheat Family)

Close up of Eriogonum viridulum by James Reveal
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Close up of Eriogonum viridulum by James Reveal
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Taxonomic Comments

First described by James Reveal in 1966 (Flora of North America 1993+). Weber and Whittmann (2012) list as a synonym under Eriogonum brevicaule. Flora of North America (1993+) include E. viridulum as an accepted taxon, and list E. brevicaule var. viridulum as a synomym. Welsh et al. (1993) list E. brevicaule var. viridulum as the accpted name. Ackerfield (2012) does not include this taxon as it is known in Colorado only from one specimen, housed at the University of Colorado herbarium.

Ranks and Status

Global rank: G4Q
State rank: SH
Federal protection status: BLM Sensitive
State protection status: None

[+] Description and Phenology

Eriogonum viridulum: no artwork available

General description: Herbs, spreading, not scapose, 1-3.5 1-4 dm, glabrous, bright green. Stems spreading, without persistent leaf bases; caudex stems absent; aerial flowering stems erect, slender, solid, not hollow, 0.5-1.2 dm, glabrous, tomentose among leaves. Leaves sheathing 1-6 cm, 1 per node; petiole 0.1-0.2 cm, tomentose or glabrous; blade linear or rarely narrowly elliptic, 1-4 0.1-0.5 cm, densely white-tomentose abaxially, glabrous and green adaxially, margins usually tightly revolute. Inflorescences cymose, 3-15 2-10 cm; branches dichotomous, glabrous; bracts 3, scalelike, narrowly triangular, 1-3 mm. Peduncles absent or erect, slender, 0.05-0.2 cm. Involucres 1 per node, turbinate, 2-3 1.5-2 mm, glabrous; teeth 5, erect, 0.5-0.8 mm. Flowers 1.5-2 mm; perianth yellow, glabrous; tepals connate proximal 4- 3, slightly dimorphic, those of outer whorl ovate, 1-1.2 wide, those of inner whorl oblong, 0.7-0.8 mm wide; stamens exserted, 1.5-2 mm; filaments pilose proximally. Achenes brown, 1.5-2 mm, glabrous (Flora of North America 1993+).

Look Alikes: Eriogonum viridulum has a distinctive upright inflorescence composed of numerous, bright green and glabrous branches bearing essentially sessile involucres. These features and the linear to narrowly elliptic leaf blades that are typically tightly revolute combine to distinguish the species from the related E. brevicaule var. brevicaule (Flora of North America 1993+).

Phenology: Flowers July through October (Flora of North America 1993+).

[+] Herbarium Photos

Images of Eriogonum viridulum housed at the Colorado State University Herbarium.

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[+] Habitat

Habitat of Eriogonum viridulum: not available

Habitat information specific to the Colorado location is not known. The Flora of North America (1993+) reports that this species is found on sandy or silty flats or clay slopes and hills, in saltbush or sagebrush communities, or in pinyon-juniper woodlands.

Elevation Range: 5,574 - 5,991 feet (1,699 - 1,826 meters)

[+] Distribution

Distribution of Eriogonum viridulum in Colorado according to mapped land ownership/management boundaries (CNHP 2012, COMaP v9 ).
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Distribution of Eriogonum viridulum in Colorado
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Colorado endemic: No
Global range: Known from Utah, Arizona, and Colorado (USDA NRCS 2012).
State range: Known from one location in Moffat County (Colorado Natural Heritage Program 2012).

[+] Threats and Management Issues

This species is only known from one historical record in Colorado.

[+] References

    • Flora of North America Editorial Committee, ed. (FNA). 1993+. Flora of North America North of Mexico. Oxford Univ. Press, New York, Oxford.
    • Flora of North America Editorial Committee. 2005. Flora of North America North of Mexico. Vol. 5. Magnoliophyta: Caryophyllidae: Caryophyllales, Polygonales, and Plumbaginales. Oxford Univ. Press, New York. vii + 656 pp.
    • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
    • Lavender, A.E., M.M. Fink, S.E. Linn, D.M. Theobald. 2011. Colorado Ownership, Management, and Protection v9 Database. Colorado Natural Heritage Program and Geospatial Centroid, Colorado State University, Fort Collins, CO. (30 September).
    • USDA, NRCS. 2013. The PLANTS Database. National Plant Data Team, Greensboro, NC 27401-4901 USA.
    • Weber, W. A. and R. C. Wittmann. 2012. Colorado Flora, Western Slope, A Field Guide to the Vascular Plants, Fourth Edition. Boulder, Colorado. 532 pp.
    • Welsh, S.L., N.D. Atwood, S. Goodrich, and L.C. Higgins (eds.) 1993. A Utah flora. 2nd edition. Brigham Young Univ., Provo, Utah. 986 pp.
    • Wiley-Eberle, K.L. 1980. Threatened and Endangered Plant Species: Habitat Classifications, Descriptions, and Associated Plant Species. Unpublished Report Prepared for the Colorado Natural Areas Program, Denver CO.

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