Orbexilum pedunculatum(Mill.) Rydb.

Sampson's snakeroot

WFO wfo-0000172321 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Orbexilum pedunculatum, photographed by Robert Hoard
fig. a Robert Hoard, CC0 1.0 / 2022-05-28 / obs. 201426636
Orbexilum pedunculatum, photographed by Daniel S. Katz
fig. b Daniel S. Katz, CC BY 4.0 / obs. 202267937
Orbexilum pedunculatum, photographed by john_hall
fig. c john_hall, CC BY 4.0 / obs. 200556675
Orbexilum pedunculatum, photographed by John Kees
fig. d John Kees, CC0 1.0 / obs. 196662857
Orbexilum pedunculatum, photographed by Samuel A Schmid, PhD, PWS
fig. e Samuel A Schmid, PhD, PWS, CC BY 4.0 / obs. 195149688
Orbexilum pedunculatum, photographed by drnancyjackson
fig. f drnancyjackson, CC BY 4.0 / obs. 193178301
Orbexilum pedunculatum, photographed by john_hall
fig. g john_hall, CC BY 4.0 / obs. 135704170
Orbexilum pedunculatum, photographed by Elias
fig. h Elias, CC BY 4.0 / obs. 134893882

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 17 botanical countries

Regions where Orbexilum pedunculatum is native: Alabama, Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, Ohio, Oklahoma, South Carolina, Tennessee, Texas, Virginia AlabamaFloridaGeorgiaIllinoisIndianaKansasKentuckyLouisianaMississippiMissouriNorth CarolinaOhioOklahomaSouth CarolinaTennesseeTexasVirginia
Native distribution of Orbexilum pedunculatum, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows.
RegionTDWG codeContinent
Alabama ALA NORTHERN AMERICA
Florida FLA
Georgia GEO
Illinois ILL
Indiana INI
Kansas KAN
Kentucky KTY
Louisiana LOU
Mississippi MSI
Missouri MSO
North Carolina NCA
Ohio OHI
Oklahoma OKL
South Carolina SCA
Tennessee TEN
Texas TEX
Virginia VRG

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Flowering 159 in flower of 172 examined

Peak flowering in May. Each bar is the share of Orbexilum pedunculatum observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 159 of 172 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 9 months have fewer than 5 examined observations, so no proportion is drawn for them. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.

Also published as 7 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Desmodium pedunculatum (Mill.) DC.
  • Hedysarum pedunculatum Mill.
  • Orbexilum pedunculatum var. eglandulosum (Elliott) Isely
  • Orbexilum pedunculatum var. pedunculatum
  • Psoralea eglandulosa Elliott
  • Psoralea pedunculata (Mill.) Vail
  • Psoralea psoralioides var. eglandulosa (Elliott) F.L.Freeman

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
  4. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.