The only mature plant that has been confused with gypsum wild buckwheat is limewater brookweed (Samolus ebracteatus). The foliage of limewater brookweed is superficially similar to gypsum wild buckwheat both during the growing season and when senesced. Gypsum wild buckwheat can be discerned from limewater brookweed by its colorful (yellow to pink) petioles.

Seedling and juvenile plants of gypsum ringstem (Anulocaulis gypsogenus) are sometimes confused for gypsum wild buckwheat juveniles. Young gypsum ringstem leaves are more succulent than gypsum wild buckwheat leaves, and they can also be distinguished by the red- to purple-ish pigmentation on the undersides on their leaves.

The weight of gypsum wild buckwheat plants has not been measured. Gypsum wild buckwheat seeds weigh an average of 4 to 5 micrograms each (USFWS 2021, no page number).

Gypsum wild buckwheat plants have bold-green leaves, yellow to pink petioles, light green peduncles, and bright yellow flowers. Subterranean stems are reddish-brown and enclosed within papery reddish-brownish sheaths. When gypsum wild buckwheat leaves deteriorate with age, they become brick-red in color. There are no gypsum wild buckwheat root observations documented.

Gypsum wild buckwheat plants branch underground, and genetically unique plants can’t be determined without genetic analysis. Each branch emerges from the soil surface as clusters of one to several basal rosettes, and each rosette is typically capable of producing a single erect, compound, cymose inflorescence (Reveal 1976, p. 441; BLM 2017, no page number). When rosette apical meristems are injured (such as by hail), gypsum wild buckwheat may produce multiple inflorescences per rosette.

Measurements (BLM 2017, no page number)

Height (vegetative and flowering individuals): 0.8 to 6.3 (median of 1.5) in (2 to 159 [median of 37] mm)

Vegetative width: 0.3 to 9.3 (median of 2.9) in (7 to 237 [median of 73] mm)

Clump count: 1 to 6 (median of 1)

Rosette count: 1 to 17 (median of 2)

Inflorescence width: to 6.3 (median of 4.8) in (to 159 [median of 123] mm)

Inflorescence count: 1 to 6 (median of 1)

Gypsum wild buckwheat leafs-out by late-March, sets flower buds starting in mid-April, begins flowering by late April, and blooms fully after mid-May. Seeds ripen beginning in late-June, are typically at peak ripeness in early-July, and have mostly dispersed by late-July. Seeds overcome dormancy through moist, and cold stratification in year one. Eriogonum species don’t seem to have a dormancy mechanism for maintaining a viable seedbank, so annual successful seed production is important to Buckwheat’s viability. Seedling emergence is presumed to occur infrequently, depending on suitable soil moisture conditions, starting in mid-April and extending throughout the growing season. In addition to suitable soil conditions and weather events, successful reproduction is supported by healthy populations of local plant species (to disperse predation and to support native pollinator species). While flowering and seed-production are reliable even during drought conditions, observed gypsum wild buckwheat seedling germination and seedling survival are low. It’s likely that, while in most years few to no new genetically unique individuals are recruited into gypsum wild buckwheat populations, gypsum wild buckwheat experiences significant episodic seedling recruitment events (rare but periodic climatic events that flush seedlings) that are not captured within the timeframe of existing recruitment observations.

Gypsum wild buckwheat reproduces sexually by pollination of ovaries. It has perfect, or bisexual, flowers that may be partially self-compatible. Self-fertilized ovules, however, are likely produce fewer and lower quality seeds. Gypsum wild buckwheat pollination success is more likely to depend on a diverse community of pollinators that on a single, specialized pollinator. 

Gypsum wild buckwheat seeds are small, camouflaged within senesced tepals, and notoriously difficult to detect. 55 to 74% of gypsum wild buckwheat inflorescences produce seed, and each inflorescence produces between 0 and 95 filled seeds. Estimates of seed viability in Eriogonum species range from less than one percent to 69%.

Gypsum wild buckwheat dispersal is unstudied, but the seeds of Eriogonum species are dispersed by wind, rain, streams, and animals. We assume that gypsum wild buckwheat seed is primarily dispersed within populations by sheet run-off, ants, and small mammals. We also assume that dispersal beyond populations by birds or drainage flooding is rare.

Gypsum wild buckwheat seedling recruitment of genetically unique individuals is low, and—in most years—does not compensate for mortality. In multiple studies, few definite gypsum wild buckwheat seedlings were observed. Gypsum wild buckwheat demographic plots consist of 0.24 to 0.49% seedlings, or approximately 1 seedling for every 200 to 400 established individuals. Seedlings have an average survival rate of 28.57% from July of year one to July of year two. 

For gypsum wild buckwheat germination to occur, viable seeds must lodge in a suitable microsite, overcome dormancy, and experience germination-inducing soil moisture, temperature, and solar exposure conditions within the range of the seed’s longevity. Gypsum wild buckwheat seed longevity is unknown, and most Eriogonum seeds may not survive beyond one year in wild seed banks. We assume that significant gypsum wild buckwheat seedling establishment occurs when infrequent climatic episodes suitable for seed germination and seedling establishment occur during the growing season. Several successive days of substantial rainfall and cloudy conditions appear to be needed to soften the surface crust, allowing seeds to settle into the substrate for germination and for the plants to break through the physical soil crust. New plants typically become reproductive within 3 to 5 years, or when they reach a size of 2 in (50 mm).

Gypsum wild buckwheat longevity is estimated at up to 22 to 99 years as a perennial, woody-stemmed, iteroparous, non-clonal, self-incompatible, animal-pollinated plant with no seedbank that grows in open habitat.

Gypsum wild buckwheat’s natural stressors include harsh climate, harsh soils, and trampling and utilization by wildlife. Gypsum wild buckwheat can avoid dehydration by strategic dormancy (staying subterranean when climatic conditions are unfavorable) and may be able to liberate water from hydrated gypsum crystals (crystallization water). Root associations with soil microorganisms (such as arbuscular mycorrhizal fungus) help gypsum wild buckwheat to assimilate scarce nutrients and may help gypsum wild buckwheat to weather gypsum water. These resiliencies can incite excessive herbivory; during growing season drought, gypsum wild buckwheat may be one of the only active plant species available for forage in an area. When assaulted (chemically attacked, defoliated, crushed, or displaced), gypsum wild buckwheat re-sprouts as soon as conditions conducive to growth resume.  When displaced or dug up, gypsum wild buckwheat responds by branching out new shoots from its subterranean stems.

Gypsum wild buckwheat occurs within geological formations that contain gypsum deposits, and occupies facies of at least 40% gypsum within these formations (Spurrier 1989, p. 28). Gypsum is composed of calcium sulfate and crystalized water (CaSO4·2H2O) and is highly soluble. The solubility of gypsum creates karst landscapes. In limestone landscapes, plant roots have been observed occupying karst soil pockets (karst cavities filled with soil). These soil pockets are thought to provide additional sources of water and nutrients for plants (Estrada-Medina et al. 2010, p. 12).

Gypsum wild buckwheat is endemic to hypergypsic gypsum soils, “soils having gypsum as a major component, often more than 50%” (Herrero 1992, Abstract). These soils are primarily mapped as the “gypsum land-cottonwood complex, 0 to 3 percent slopes” (GC) soil map unit (BLM 2020, no page number; United Stated Department of Agriculture, Soil Conservation Service [USDA-SCS] 1971, p. 22). Soil depth also likely plays a role in microhabitat suitability (Spurrier 1989, p. 28; BLM 2018, no page number). Sampled occupied soils were typically 10 cm (4 in) in depth (BLM 2018, no page number).

Hypergypsic soils may alleviate water stress in arid environments. Shallow-rooted plants commonly use crystallization water in gypsum environments (Palacio et al. 2014, p. 2). During the summer, “gypsum from the most superficial layers of the soil can be easily dehydrated, releasing water molecules profitable to plants and potentially also other organisms” (Palacio et al. 2014, p. 4). During cooler periods, plants and soil microorganisms (such as arbuscular mycorrhizal fungus) may still be able to chemically weather water from gypsum (Palacio et al. 2014, p. 4). Use of crystallization water by gypsum wild buckwheat is unknown but consistent with observations of gypsum wild buckwheat remaining active when drought is intense (Palacio et al. 2014, p. 2).

Chemically, hypergypsic soils are toxically abundant in some plant nutrients (such as calcium, sulfur, and magnesium), and deficient in other nutrients (such as nitrogen, potassium, and phosphorus) (Escudero et al. 2015, p. 7). Gypsophiles either manage nutrient toxicities through special adaptations (such as accumulation) or stress tolerance (Moore et al. 2014, pp. 6-7, Palacio 2007, p. 340); leaf nutrient analyses are needed to determine which strategy gypsum wild buckwheat employs. Symbiotic relationships with soil microorganisms likely facilitate gypsum wild buckwheat’s resilience to soil nutrient deficiencies. Dominant gypsophile species of New Mexico are found to have generally higher levels of colonization by arbuscular mycorrhizal fungus when compared to nearby non-gypseous grassland flora, and it’s hypothesized that gypsum floras may be co-evolving gypsum specialization in association with these and additional symbiotic microorganisms (Moore et al. 2014, p. 11).

Biological soil crusts (biocrusts) play an important role in soil water and nitrogen availability in arid and semiarid ecosystems. Well-established biocrusts conserve soil moisture by increasing water infiltration and decreasing evaporative losses of water (Whitney et al. 2017, p. 3). Biocrusts also fix nitrogen. Most of the nitrogen fixed by biocrusts is released into surrounding soils, and biocrust communities may be the principle suppliers of soil nitrogen in some desert ecosystems (Austin et al. 2004, p. 229). Biological soil crusts perform a crucial role in the long-term maintenance of gypseous clay soils and the overall functionality of gypsum ecosystems (Escudero et al. 2015, p. 13).

Gypsum wild buckwheat is a gypsophile that depends on broad, gently to moderately sloping, slightly erosional escarpments or hills of hypergypsic, slightly alkaline, loose, moderately developed clay soils containing adequate soil moisture—possibly including hydrated gypsum (water of crystallization)—and soil nutrients for survival and recruitment. These hypergypsic soils are vulnerable to erosion and compaction, and gypsum wild buckwheat's habitat is easily rendered locally unsuitable in places where natural or human-caused surface disturbance has displaced or intensely compacted these soils. Known gypsum wild buckwheat occupied areas occur adjacent to riparian riparian
Definition of riparian habitat or riparian areas.

Learn more about riparian corridors and near (within approximately 3 km [1.8 mi] of) springs in the Chihuahua Deserts ecoregion. Canopy cover is low and sparse. Known populations occur where elevations range from 990 to 1090 m (3,240 to 3,580 ft.) and where average annual precipitation ranges from 33.6 to 34.7 cm (13 to 14 in). Temperatures range from an average low of -2° C (29° F) in January to an average high of 35° C (95° F) in June. The growing season starts by early-April and extends to late-October.

Unsuitable habitat occurs within, further upland from, and below suitable gypsum wild buckwheat habitats and consists of loamy soils hosting riparian woodlands, dense grasslands, or dense (impassable at 10 m intervals) shrubland.