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Viola calcicola

R.A. McCauley & H.E. Ballard

Limestone Violet

G2Imperiled (G2G3) Found in 1 roadless area NatureServe Explorer →
G2ImperiledGlobal Rank
Medium - lowThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.150586
Element CodePDVIO04490
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderViolales
FamilyViolaceae
GenusViola
Concept Reference
McCauley, R.A., and H.E. Ballard, Jr. 2013. Viola calcicola (Violaceae), a new endemic violet from the Guadalupe Mountains of New Mexico and Texas. Journal of the Botanical Research Institute of Texas 7:9-20.
Taxonomic Comments
This species was first described in 2013 (McCauley and Ballard 2013). The Flora of North America (vol. 6, 2015) did not include it, due to time contraints, "When this treatment was being finalized, Viola calcicola R. A. McCauley and H. E. Ballard was described as new. Time constraints prevented it from being incorporated. Viola calcicola is acaulescent, heterophyllous, has short, vertical rhizomes, nearly white to purple corollas, and occurs only on limestone substrates. It is endemic to the Guadalupe Mountains of Texas and New Mexico" (Flora of North America Editorial Committee 2015). It is considered to be a distinct species in a revised phylogenetic classification of the Violaceae (Marcussen et al 2022).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2024-07-29
Change Date2024-07-29
Edition Date2024-07-29
Edition AuthorsA. Treher (2013), rev. C. Nordman (2018), rev. Treher (2019), rev. C. Nordman (2024).
Threat ImpactMedium - low
Range Extent<100 square km (less than about 40 square miles)
Number of Occurrences6 - 20
Rank Reasons
Viola calcicola is a narrowly endemic species limited to springs and canyons on rocky limestone areas in the Guadalupe Mountains in west Texas and southern New Mexico. There are fewer than twenty occurrences within the entire range, which is less than 100 square km (40 square miles). There are protected populations in Texas on the Guadalupe Mountains National Park and on other federal lands nearby in New Mexico.
Range Extent Comments
Viola calcicola occurs along the eastern escarpment of the Guadalupe Mountains of Culberson County in west Texas and Eddy County in southern New Mexico. Range extent was estimated to be 63 square kilometers, using herbarium specimens and NatureServe Network occurrence data collected between 1989 and 2024 (McCauley and Ballard 2013, FNA 2015, Sivinski 2016, Allred et al. 2020, GBIF 2024, NatureServe 2024, NMNHP 2024, SEINet 2024).
Occurrences Comments
There are about twenty documented locations of Viola calcicola (McCauley and Ballard 2013, SEINet 2024). Some of these are close together, and several locations documented along one canyon probably represent the same population (McCauley and Ballard 2013, NMNHP 2024, SEINet 2024). By applying a 1 km separation distance to herbarium specimens and NatureServe Network occurrence data documented between 1989 and 2024, it is estimated that there are about ten and between six and twenty occurrences rangewide (GBIF 2024, NatureServe 2024, NMNHP 2024, SEINet 2024).
Threat Impact Comments
The rugged, inaccessible nature of this plant's habitat protects it from any impacts of land use (Sivinski 2016). Recreation may be a threat at heavily visited sites. Severe drought, associated with climate change, is a threat and may become more frequent in the future.
Ecology & Habitat

Description

Viola calcicola is an acaulescent herbaceous perennial. It is heterophyllous, meaning the leaves are variable in shape. It has short, vertical rhizomes, nearly white to purple corollas, and occurs only on limestone substrates (Flora of North America Editorial Committee 2015).

Diagnostic Characteristics

There are no other Viola species with white (with purple lines) or purple flowers in the Guadalupe Mountains. Viola guadalupensis has flowers with yellow petals. In the adjacent Sacramento Mountains, Viola nephrophylla has purple petals, but is quickly distinguished, it has some pubescence on its petal spur (Sivinski 2016).

Habitat

Viola calcicola grows in the cracks of Permian Age limestone in sheltered canyons and springs and mostly on limestone rocks in close proximity to water like rocky stream terraces or canyon walls flanking streams (McCauley and Ballard 2013). It is commonly found under an overstory of Arbutus xalapensis, Quercus muhlenbergii, and Acer grandidentatum (McCauley and Ballard 2013, SEINet 2024).

Reproduction

Viola calcicola has chasmogamous and cleistogamous flowers, blooming in April and May (Sivinski 2016). It spreads by rhizomes.
Terrestrial Habitats
Bare rock/talus/scree
Palustrine Habitats
Riparian
Other Nations (1)
United StatesN2
ProvinceRankNative
TexasSNRYes
New MexicoS1Yes
Threat Assessments
ThreatScopeSeverityTiming
6 - Human intrusions & disturbanceRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
6.1 - Recreational activitiesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
11 - Climate change & severe weatherLarge (31-70%)Moderate - slightHigh (continuing)
11.2 - DroughtsLarge (31-70%)Moderate - slightHigh (continuing)

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Plant Characteristics
DurationPERENNIAL, SPRING-FLOWERING
Economic Value (Genus)No
Roadless Areas (1)
New Mexico (1)
AreaForestAcres
South Guadalupe MountainsLincoln National Forest20,930
References (10)
  1. Allred, K.W., E.M. Jercinovic, and R.D. Ivey. 2020. Flora Neomexicana III: An Illustrated Identification Manual, Second Edition. Part 2: Dicotyledonous Plants.
  2. Flora of North America Editorial Committee (FNA). 2015. Flora of North America north of Mexico. Vol. 6. Magnoliophyta: Cucurbitaceae to Droserceae. Oxford University Press, New York. 496 pp + xxiv.
  3. Global Biodiversity Information Facility (GBIF). 2024. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2024).
  4. Marcussen, T., H. E. Ballard, J. Danihelka, A. R. Flores, M. V. Nicola and J. M. Watson. 2022. A revised phylogenetic classification for Viola (Violaceae). Plants 11: 2224. Online. Available: https://doi.org/10.3390/plants11172224 (accessed 2024).
  5. McCauley, R.A., and H.E. Ballard, Jr. 2013. <i>Viola calcicola</i> (Violaceae), a new endemic violet from the Guadalupe Mountains of New Mexico and Texas. Journal of the Botanical Research Institute of Texas 7:9-20.
  6. NatureServe. 2024. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  7. NatureServe. Unpublished. Concept reference for taxa which have not yet been described; to be used as a placeholder until a citation is available which describes the circumscription of the taxon.
  8. Sivinski, R. 2016. New Mexico rare plants: <i>Viola calcicola</i>. Limestone violet. New Mexico Rare Plant Technical Council, Albuquerque, New Mexico. Information Compiled by: Robert Sivinski, 2016. Online. Available: http://nmrareplants.unm.edu/rarelist_single.php?SpeciesID=243 (Accessed 2018).
  9. Southwest Environmental Information Network (SEINet). 2024. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2024).
  10. <span><span>New Mexico Natural Heritage Program (NMNHP). 2023. Element Subnational Ranking Form: <i>Viola calcicola</i> in Biotics 5 database. NatureServe, Arlington, Virginia (accessed 29 July 2024).</span></span>