Montana Field Guide

PLANTS: A tufted, perennial, up to 3 dm tall, with leaves and stems covered in white-wooly hairs. It has a branched, woody stem just below the soil surface (caudex). Source: Lesica et al. 2012.

LEAVES: Mostly basal, 1–3 cm long by 2-7 mm wide, linear to oblong (narrowly oblanceolate or spatulate), and covered with matted wooly hairs (tomentum). Source: Lesica et al. 2012.

INFLORESCENCE: Flowering stems are ascending to erect, 5–20 cm, and tomentose. The inflorescence is an open umbellate cyme, usually branching 3 or more times from a common base that has at least 2 scale-like bracts and sometimes a leaf. The involucre, which subtends the flowering pedicle, is wooly-hairy, 2-4 mm, with 5 united erect lobes. The flowers are comprised of 6 sparsely hairy yellow tepals (similar petals and sepals) with 9 exserted stamens. Tepals are 1-3 mm long. The flower is rounded at the base (cup-shaped) not tubular. Achenes are 2–3 mm long. Sources: Lesica et al. 2012; McGregor et al. 1986.

Montana plants belong to variety canum.

The name “Eriogonum” means hairy knees referring to the wooly nodes and stems (Giblin et al. [eds.] 2018). The specific name and variety mean “hairy, short-stem”, also pointing out the tomentum of the plant (Gledhill 1990).

Flowering from June to September in Montana (www.pnwherbaria.org).

Eriogonum is a diverse genus in south-central Montana, represented by at least 10 species. Most species have a tight inflorescence, some resembling a ball of flowers (e.g., E. ovalifolium, E. mancum, E. caespitosum, E. pauciflorum, and E. flavum) unlike the spreading-open flowering heads of Parasol Buckwheat. Three other species are annuals (E. annuum, E. cernuum, and E. salsuginosum). Parasol Buckwheat can be distinguished by the following combination of characteristics:

Parasol Buckwheat - Eriogonum brevicaule var. canum, PSOC
*Inflorescence: Spreading and open, not flat-topped.
*Flowers: Yellow, sparsely hairy (not glandular) sepals and petals (collectively called tepals). The tepals attach (connate) at their bases and are cup-shaped.
*Roots: A branched, woody caudex.

In the U.S. eight varieties of Eriogonum brevicaule are recognized (Reveal in FNA 2005). Variety canum is identified as having flowering stems and inflorescence branches covered with dense, soft, and interwoven hairs (tomentose) and tepals that are pubescent (though sparsely) (Reveal in FNA 2005).

Barren, calcareous, stony or clayey soils of badlands, exposed ridges, and slopes from valleys to the lower montane zone in Montana (Reveal in FNA 2005; Lesica et al. 2012).

In Wyoming, this species grows on barren slopes, terraces, and flats of Chugwater redbed clays, or reddish clay and dolomite gravel of the Goose Egg Formation. The setting is in cushion plant communities or openings in juniper woodland and sagebrush steppe (Fertig et al. 1994; Heidel and Fertig 2000).

Parasol Buckwheat occurs in sparsely vegetated soils in mixed grasslands, sagebrush, and limber pine-juniper woodland communities.

ASSOCIATED PLANTS
Herbarium specimens (www.pnwherbaria.org) listed many plants as occurring with Parasol Buckwheat: Low Sagebrush (Artemisia arbuscula), Longleaf Wormwood (Artemisia longifolia), Big Sagebrush (Artemisia tridentata), Summer Milkvetch (Astragalus hyalinus), Shadscale (Atriplex confertifolia), Thread-leaved Sedge (Carex filifolia), Cock’s-comb Cat’s-eye (Crypthantha celosioides), Bluebunch Wheatgrass (Elymus spicatus), Rubber Rabbitbrush (Ericameria nauseoa), Broom Snakeweed (Gutierrezia sarothrae), Basin Daisy (Platyschkuhria integrifolia), and Black Greasewood (Sarcobatus vermiculatus).

In Wyoming, Parasol Buckwheat is found to be associated with Rayless Tansy-aster (Machaeranthera grindelioides), Hooker's Sandwort (Eremogone hookeri), Stemless Four-nerved-daisy (Hymenoxys acaulis), Summer Milkvetch (Astragalus hyalinus), and Bluebunch Wheatgrass (Elymus spicatus).

POLLINATORS
The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus bifarius, Bombus centralis, Bombus flavifrons, Bombus huntii, Bombus melanopygus, Bombus mixtus, Bombus ternarius, Bombus occidentalis, Bombus insularis, and Bombus flavidus (Thorp et al. 1983, Koch et al. 2012, Williams et al. 2014).

RESEARCH NATURAL AREAS and AREA OF CRITICAL ENVIRONMENTAL CONCERN PROGRAM
The Research Natural Area (RNA) program is a nationwide system created to protect a network of federally administered public lands established for the purpose of scientific research, maintaining biological diversity, and education (USFS 2014). The intent is to designate RNAs that represent the full array of North American ecosystems with their biological communities, habitats, natural phenomena, and geological and hydrological formations. These intact protected areas are managed to maintain their natural and primitive character with a minimum of human disturbance. Each RNA also serves as a baseline of ecological information that can be used to compare against other similar, yet managed ecological systems.

A type of RNA is the Area of Critical Environment Concern (ACEC). The ACEC program was established in the 1976 Federal Lands Policy and Management Act and is managed by the Bureau of Land Management (BLM) (Wikipedia Contributors 2020). Places designated as ACECs require special management to protect important historical, cultural, and scenic values, fish and wildlife, or other natural resources (BLM 2021). The BLM has extended the purpose of RNAs to that of preserving gene pools of typical and endangered plants and animals (BLM 2015; BLM 2021).

Pryor Foothill RNA/ACEC
This RNA-ACEC was established in the Approved Resource Management Plan by the MT/Dakotas BLM, Billings Field Office, recommended for approval by the MT/Dakotas BLM State Director in 2015, and is awaiting final approval by the U.S Congress (BLM 2015). The RNA-ACEC is approximately 2,606 acres in size. The management goals for the Pryor Foothills RNA/ACEC are to protect a large concentration of BLM's special status plant species and rare plant communities (unique vegetation) and to protect significant historic and cultural values in the Gyp Springs area. With Parasol Buckwheat, populations are very common in the Pryor Foothill RNA-ACEC. Plants are frequently found outside of the RNA-ACEC where specific habitat is present in Carbon, Big Horn, and Yellowstone Counties. See Range Comments.

The area encompassing Gypsum Creek and Crooked Creek, which includes the present-day Pryor Foothill RNA/ACEC was recognized in 1991 as having the highest concentration of high-priority plant species' populations (Lesica and Achuff 1992). Surveys from the 1980's to 1990's found populations of eight rare species Astragalus geyeri, Astragalus oreganus, Camissonia andina, Cleome lutea, Grayia spinosa, Leptodactylon caespitosum, Malacothrix torreyi, and Mentzelia pumila, of which remain as either Montana Species of Concern or Potential Species of Concern. The area's concentration of unique and diverse plant species partially results from diverse habitats, terrain that varies from highly dissected foothills with deep canyons to broad alluvial valleys, and soils derived from calcareous standstone, Chugwater sandstone, and limestone. In their 1992 report the authors recommended that this area would serve as the best choice for a single reserve in the Pryor Mountain Desert (Lesica and Achuff 1992).

In Montana, current and potential long-term threats to Parasol Buckwheat include (Lesica and Achuff 1992; Montana Native Plant Society 2009 and 2021):

Mining: Gypsum is a common mineral found in the Chugwater Formation. Gypsum claims have been made on public lands in vicinity of Parasol Buckwheat sites. Bentonite mining could occur in vicinity of other Parasol Buckwheat sites. Potential negative impacts from mining activities include direct removal and trampling of plants. Potential indirect negative impacts from mining activities include disturbance to habitat from soil erosion, soil compaction, and colonization by invasive species. Soils in the Chugwater Formation are known to be very susceptible to erosion.

Invasive Species: The arid landscape in which Parasol Buckwheat occurs is predominately in native, intact habitat. However, Cheatgrass (Bromus tectorum), African mustard (Malcolmia africans), and Halogeton (Halogeton glomeratus) are known to occur along roads near to some Parasol Buckwheat occurrences. Halogeton outcompetes many native species by increasing the salinity of the soil (Sauer 1988) and has become locally common in the Pryor Mountain Desert region (Lesica and Achuff 1992). There is the potential for negative impacts based on the assumption that these exotics would be more competitive for soil water and nutrient resources, thus displacing native plants.

Off-road Vehicle Recreation: Off-road vehicle (ORV) use commonly occurs further north in Pryor Mountains. In the Big Horn Canyon National Recreational Area one species occurrence grows along a road and may be vulnerable to vehicular disturbance. Where ORV use overlaps with Parasol Buckwheat populations there is the potential to damage plants by trampling, compacting soils, and increasing erosion. STATE THREAT SCORE REASON
Reported threats to Montana's populations of Parasol Buckwheat are due to multiple, likely interacting negative impacts in its roadside habitat (MTNHP Threat Assessment 2021).