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Viola lithion

N. Holmgren & P. Holmgren

Rock Violet

G1Critically Imperiled (G1G2) Found in 4 roadless areas NatureServe Explorer →
G1Critically ImperiledGlobal Rank
HighThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.148270
Element CodePDVIO04300
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderViolales
FamilyViolaceae
GenusViola
Other Common Names
rock violet (EN)
Concept Reference
Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, N.C.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2023-03-14
Change Date2005-04-21
Edition Date2023-03-14
Edition AuthorsJ. Morefield (2005), rev. L. Oliver (2011), rev. C. Nordman (2023).
Threat ImpactHigh
Range Extent250-1000 square km (about 100-400 square miles)
Number of Occurrences1 - 5
Rank Reasons
Viola lithion is known from high elevations of two disjunct mountain ranges in eastern Nevada and perhaps adjacent northwestern Utah. The frequency of appropriate habitat between these ranges suggest that additional occurrences may remain to be discovered. It occurs in remote, rocky areas, threats include localized impacts from rock-climbing activities, and the effects of extreme or long-term drought and temperature extremes associated with climate change. Some occurrences are protected within the Currant Mountain Wilderness Area, on the Humboldt-Toiyabe National Forest.
Range Extent Comments
Viola lithion occurs in the western United States, in small and widely disjunct areas, in the White Pine Range of east-central Nevada, in the Pilot Range of northeastern Nevada and perhaps adjacent northwestern Utah. The range extent of the likely extant occurrences (all in Nevada) is 322 square kilometers (Flora of North America Editorial Committee 2015, Holmgren 1992, iNaturalist 2023, NatureServe 2023, SEINet 2023). The original collection by Cottam in 1929, presumed to be in Utah, has subsequently been determined to have been made at slightly higher elevation in the Pilot Range, just to the west across the state line in Nevada. Its occurrence in Utah needs to be confirmed. A single specimen reported from the Blackfoot Mountains of southeastern Idaho (N. H. Holmgren #5425, NY), was identified as the more common Viola adunca, with petals white at the base, rather than yellow (SEINet 2023).
Occurrences Comments
There are estimated to be three extant occurrences of in Nevada, plus an historical occurrence which may have been in Utah, but more likely was at higher elevation in nearby Nevada (NatureServe 2023, SEINet 2023).
Threat Impact Comments
Viola lithion occurs in remote, steep, high elevation, threats include the potential for localized impacts from rock-climbing activities, and the effects of droughts and temperature extremes associated with climate change. While some occurrences are protected within the Currant Mountain Wilderness Area, geothermal leasing has been proposed for the Ely District of Humbold-Toiyabe National Forest, and other rock violet occurrences could be impacted by activities related to geothermal energy activities (US Forest Service 2011, Forest Projects).
Ecology & Habitat

Description

A perennial herb, 0.5-1.5 dm tall, with egg-shaped or triangular leaves. Flower petals are blue to pale violet, yellow at their bases, and with purple lines. In bloom from June to August.

Habitat

Viola lithion occurs in seasonally wet crevices in steep carbonate or quartzite outcrops in shaded northeast-facing avalanche chutes and cirque headwalls at 2200-3100 m elevation, in the subalpine conifer zone with Primula parryi, Valeriana occidentalis, Symphoricarpos oreophilus, Ribes montigenum, Heuchera rubescens, Aquilegia scopulorum, Thalictrum fendleri, Pinus flexilis, and Populus tremuloides (Flora of North America Editorial Committee 2015, Holmgren 1992, SEINet 2023).

Reproduction

Blooms June to August (Holmgren 1992).
Terrestrial Habitats
Bare rock/talus/screeCliff
Other Nations (1)
United StatesN1
ProvinceRankNative
NevadaS1Yes
UtahS1Yes
Threat Assessments
ThreatScopeSeverityTiming
3 - Energy production & miningRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
3.3 - Renewable energyRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
6 - Human intrusions & disturbanceSmall (1-10%)Moderate or 11-30% pop. declineHigh (continuing)
6.1 - Recreational activitiesSmall (1-10%)Moderate or 11-30% pop. declineHigh (continuing)
11 - Climate change & severe weatherPervasive (71-100%)Serious or 31-70% pop. declineHigh (continuing)
11.2 - DroughtsPervasive (71-100%)Moderate or 11-30% pop. declineHigh (continuing)
11.3 - Temperature extremesPervasive (71-100%)Serious or 31-70% pop. declineHigh (continuing)

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Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (4)
Nevada (4)
AreaForestAcres
Currant - BlackrockHumboldt-Toiyabe National Forest3,694
Currant - Duckwater EHumboldt-Toiyabe National Forest1,101
Currant - East SlopeHumboldt-Toiyabe National Forest10,101
Currant - SawmillHumboldt-Toiyabe National Forest5,364
References (8)
  1. 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.
  2. Holland, R.F. 1998. Current Knowledge and Conservation Status of <i>Viola lithion</i> N. Holmgren & P. Holmgren (Violaceae), the rock violet, in Nevada. Carson City: Nevada Natural Heritage Program, status report prepared for the U.S. Fish and Wildlife Service, Reno, Nevada.
  3. Holmgren, N. H. 1992. Two new species of <i>Viola </i>(Violaceae) from the Intermountain West, U.S.A. Brittonia 44(3): 300-305.
  4. iNaturalist. 2023. Online. Available: https://www.inaturalist.org (accessed 2023).
  5. Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, N.C.
  6. NatureServe. 2023. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  7. Southwest Environmental Information Network (SEINet). 2023. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2023).
  8. U.S. Forest Service (USFS). 2011a. Geothermal Leasing on the Humbodlt-Toiyabe National Forest. Forest Projects. Accessed online on Sept. 12. 2011 at: http://www.fs.fed.us/nepa/fs-usda-pop.php/?project=35519.