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Braya humilis

(C.A. Mey.) B.L. Robins.

Low Braya

G5Secure Found in 1 roadless area NatureServe Explorer →
G5SecureGlobal Rank
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.160338
Element CodePDBRA0D040
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderCapparales
FamilyBrassicaceae
GenusBraya
Synonyms
Braya novae-angliae(Rydb.) SorensenNeotorularia humilis(C.A. Meyer) Hedge & Leonard
Other Common Names
Braya délicat (FR) Low Northern-rockcress (EN) low northern-rockcress (EN)
Concept Reference
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.
Taxonomic Comments
The treatment in FNA (2010, vol. 7) accepts three subspecies distinct from the typical: Braya humilis ssp. ellesmerensis, ssp. maccallae, and ssp. porsildii, stating, "Three morphological forms are more sharply distinct from the general subsp. humilis amalgam and seem to have some biological significance. All of them are restricted to areas in or near regions believed to have served as glacial refugia during the Pleistocene." Kartesz (1994, 1999) did not accept any distinct infraspecific taxa.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2024-09-16
Change Date1999-05-17
Edition Date2024-09-16
Edition AuthorsN. Ventrella (2024)
Threat ImpactUnknown
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Braya humilis is a perennial forb found on sand, clay, gravel slopes, cliffs, ledges, scree, glacial moraines, and along streams, lakeshores, riverbanks, and roadsides of North American and Asia. There are over 600 occurrences of this species, which are threatened by development, rights-of-way maintenance, invasive species, succession, climate change, alteration of hydrology, and other threats in some places. Little is known about threats or trends, but with a large range extent, a high number of occurrences, abundant habitat, broad habitat preferences, and no obvious intrinsic vulnerabilities, Braya humilis is considered secure.
Range Extent Comments
Braya humilis is a widespread species, with a native range in North America and Asia (POWO 2024). In North America it occurs from Alaska and the Northwest Territories east to Newfoundland and Labrador, Canada, and Vermont, Michigan, Montana, Wyoming, and Colorado in the United States (FNA 2010). Range extent was estimated to be 54 million square kilometers using herbarium specimens and photo-based observations documented between 1993 and 2024 (GBIF 2024, iNaturalist 2024, SEINet 2024). See individual entries for distribution details about the four subspecies.
Occurrences Comments
By applying a 1 km separation distance to herbarium records and photo-based observations documented between 1993 and 2024, there are estimated to be over 600 occurrences rangewide (GBIF 2024, iNaturalist 2024, SEINet 2024).
Threat Impact Comments
Although threats are not widely documented, Braya humilis is likely threatened by development, rights-of-way maintenance, invasive species, succession, climate change, alteration of hydrology, and and other threats in some places.
Ecology & Habitat

Description

Low Braya is a short-lived perennial with 1 to several erect to prostrate stems, 3-20 cm long, which arise from a simple or branched rootcrown and taproot. The numerous basal leaves are lance-shaped and 1-3 cm long with entire or toothed margins. The widely spaced stem leaves are alternate and smaller. Foliage is sparsely to densely covered with simple and branched hairs. Flowers are borne on short stalks in terminal clusters that expand as the fruit matures. Each flower has 4 white petals, which are 3-4 mm long, 4 sepals, 4 long stamens, and 2 short stamens. The erect or spreading linear fruits are 1-3 cm long.

Diagnostic Characteristics

Braya humilis is most likely confused with species of Arabis; however, the fruits of B. humilis are round in cross-section and constricted between the seeds, while those of Arabis usually are not.

Habitat

In North America, Braya humilis occurs on sand, clay, gravel slopes, open stony slopes, gravel bars, often on limestone gravels, dolomite cliffs and slopes, limestone ledges, solifluction soils, dry alpine scree slopes, and glacial moraines, along streams, lakeshores, riverbanks, and roadsides (FNA 2010).
Terrestrial Habitats
AlpineBare rock/talus/screeCliff
Palustrine Habitats
FORESTED WETLANDRiparian
Other Nations (2)
CanadaN5
ProvinceRankNative
QuebecSNRYes
Yukon TerritoryS4Yes
NunavutS4Yes
AlbertaS3Yes
Northwest TerritoriesS4Yes
OntarioS5Yes
Island of NewfoundlandS1Yes
British ColumbiaS5Yes
ManitobaS2Yes
United StatesN5
ProvinceRankNative
AlaskaSNRYes
WyomingS1Yes
ColoradoS2Yes
MontanaS2Yes
VermontS1Yes
MichiganSXYes
VirginiaSNANo
Threat Assessments
ThreatScopeSeverityTiming
Unknown/undetermined———

—

Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (1)
Montana (1)
AreaForestAcres
Big Snowy Mountains WsaLewis and Clark National Forest88,003
References (7)
  1. Flora of North America Editorial Committee (FNA). 2010. Flora of North America north of Mexico. Vol. 7. Magnoliophyta: Salicaceae to Brassicaceae. Oxford University Press, New York. xxii + 797 pp.
  2. Global Biodiversity Information Facility (GBIF). 2024. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2024).
  3. iNaturalist. 2024. Online. Available: https://www.inaturalist.org (accessed 2024).
  4. 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.
  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. Plants of the World Online (POWO). 2024. Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Online. Available: https://powo.science.kew.org/ (accessed 2024).
  7. Southwest Environmental Information Network (SEINet). 2024. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2024).