Home/Species/ Howell's Silverpuffs

Microseris howellii

Gray

Howell's Silverpuffs

G3Vulnerable Found in 1 roadless area NatureServe Explorer →

G3VulnerableGlobal Rank

MediumThreat Impact

Identity

Unique IDELEMENT_GLOBAL.2.131565

Element CodePDAST6E090

Record TypeSPECIES

ClassificationSpecies

Classification StatusStandard

Name CategoryVascular Plant

Endemicendemic to a single state or province

KingdomPlantae

PhylumAnthophyta

ClassDicotyledoneae

OrderAsterales

FamilyAsteraceae

GenusMicroseris

Synonyms

Scorzonella howellii(A. Gray) Greene

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.

Conservation Status

Rank Method Rank calculation - Biotics v2

Review Date2025-03-19

Change Date1984-10-03

Edition Date1997-11-18

Edition AuthorsVrilakas, Sue. (1997), rev. Soteropoulos (2025)

Threat ImpactMedium

Range Extent1000-5000 square km (about 400-2000 square miles)

Number of Occurrences21 - 80

Rank Reasons

Microseris howellii is a perennial herb in open, rocky, serpentine soils of grasslands, shrublands, and savannas known only from exposures of peridotite in Josephine County, Oregon in the northwestern United States, mostly in the Illinois River Valley but also in the Lower Rogue and Applegate Subbasins. There are an estimated 34 occurrences which face threats from mining, grazing, residential development, and fire suppression. Many occurrences are located on protected lands, but management for this species is unknown.

Range Extent Comments

Microseris howellii is "known only from exposures of peridotite in Josephine County, Oregon" in the northwestern United States, mostly in the Illinois River Valley but also in the Lower Rogue and Applegate Subbasins (FNA 2006, OBIC 2018). Range extent was estimated to be 2,184 square kilometers using NatureServe Network occurrence data documented between 1990 and 2025 (RARECAT 2024, NatureServe 2025).

Occurrences Comments

By applying a 1 km separation distance to NatureServe Network occurrence data documented between 1990 and 2025, it is estimated that there are 34 occurrences rangewide (RARECAT 2024, NatureServe 2025).

Threat Impact Comments

Threats to this species include laterite and placer mining, grazing, residential development, and fire suppression (secondary succession). The threat from mining is currently low (OBIC 2018). This threat appears to be dependent on the market value of nickel and chromium which appears to be high enough to make mining commercially successful.

Ecology & Habitat

Habitat

Microseris howellii grows in open, usually "rocky serpentine soils, hillsides and alluvial flats, open shrublands and Pinus jeffreyi savannas" and grasslands (FNA 2006, OSU 2025).

Terrestrial Habitats

Shrubland/chaparralSavannaGrassland/herbaceous

Other Nations (1)

United StatesN3

Province	Rank	Native
Oregon	S3	Yes

Threat Assessments

Threat	Scope	Severity	Timing
1 - Residential & commercial development	Restricted - small	Serious or 31-70% pop. decline	Moderate (short-term)
2 - Agriculture & aquaculture	Restricted - small	Moderate - slight	High (continuing)
2.3 - Livestock farming & ranching	Restricted - small	Moderate - slight	High (continuing)
3 - Energy production & mining	Restricted (11-30%)	Serious - moderate	Low (long-term)
3.2 - Mining & quarrying	Restricted (11-30%)	Serious - moderate	Low (long-term)
7 - Natural system modifications	Restricted (11-30%)	Serious or 31-70% pop. decline	High (continuing)
7.1 - Fire & fire suppression	Restricted (11-30%)	Serious or 31-70% pop. decline	High (continuing)
7.1.2 - Suppression in fire frequency/intensity	Restricted (11-30%)	Serious or 31-70% pop. decline	High (continuing)

Plant Characteristics

DurationPERENNIAL

Economic Value (Genus)No

Roadless Areas (1)

Oregon (1)

Area	Forest	Acres
South Kalmiopsis	Siskiyou National Forests	104,477

References (7)

Flora of North America Editorial Committee (FNA). 2006a. Flora of North America north of Mexico. Vol. 19. Magnoliophyta: Asteridae, part 6: Asteraceae, part 1. Oxford University Press, New York. xxiv + 579 pp.
Kagan, J. S. 1988. Draft Species Management Guide for <i>Microseris howellii</i>. Unpublished document on file at Oregon Natural Heritage Data Base, Portland, Oregon.
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.
NatureServe. 2025. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2024. Version: 1.1.1 (released Oct 01, 2024).
Oregon Biodiversity Information Center (OBIC). 2018. Element Subnational Ranking Form: <i>Microseris howellii</i> in Biotics 5 database. NatureServe, Arlington, Virginia (accessed 19 March 2025).
Oregon State University (OSU). 2025. Oregon Flora website. Oregon State University Herbarium at Oregon State University. Online. Available: https://oregonflora.org/ (accessed 2025).

Microseris howellii

Habitat

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