Rhynchosia tomentosa(L.) Hook. & Arn.

twining snoutbean

WFO wfo-0000182211 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Rhynchosia tomentosa, photographed by Alan Weakley
fig. a Alan Weakley, CC0 1.0 / 2020-09-06 / obs. 94370620

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.

The specimen a real sheet, in a real collection

Herbarium
Smithsonian, US National Herbarium
Accession
US 3753266
Filed as
Rhynchosia tomentosa var. tomentosa
Det. by
Strong, Mark T.
Collected
M. T. Strong & C. L. Kelloff 2021-09-07
Origin
US
The sheet
View the digitised specimen (CC0 1.0)

A real pressed plant, in a real collection, under the accession number above. Not an illustration of one. The holding institution does not serve this sheet’s image to third parties, so there is no photograph here. The record is real and the link goes to it. Where we hold no openly licensed sheet for a species this section is simply absent, and where a sheet never recorded who determined it, that field stays empty rather than being filled in. Roughly half of all herbarium sheets never recorded a determiner, which is ordinary.

Native range 12 botanical countries

Regions where Rhynchosia tomentosa is native: Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, South Carolina, Tennessee, Virginia AlabamaArkansasFloridaGeorgiaKentuckyLouisianaMarylandMississippiNorth CarolinaSouth CarolinaTennesseeVirginia
Native distribution of Rhynchosia tomentosa, 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
Arkansas ARK
Florida FLA
Georgia GEO
Kentucky KTY
Louisiana LOU
Maryland MRY
Mississippi MSI
North Carolina NCA
South Carolina SCA
Tennessee TEN
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 38 in flower of 62 examined

Proportion of examined Rhynchosia tomentosa in flower, by month
Month In flower Examined Share 95% interval
Jan 0 0 too few examined
Feb 0 0 too few examined
Mar 0 0 too few examined
Apr 0 1 too few examined
May 6 9 67% 35% to 88%
Jun 17 22 77% 57% to 90%
Jul 7 9 78% 45% to 94%
Aug 7 13 54% 29% to 77%
Sep 1 6 17% 3% to 56%
Oct 0 2 too few examined
Nov 0 0 too few examined
Dec 0 0 too few examined

Peak flowering in Jul. Each bar is the share of Rhynchosia tomentosa 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. 38 of 62 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 7 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.

Where it actually grows measured, from 251 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -0.5 °C 1.9 °C 6.7 °C
Warmest month, mean daily high 30.4 °C 31.7 °C 32.8 °C
Annual rainfall 1,143 mm 1,331 mm 1,501 mm
Rainfall in the driest quarter 227 mm 266 mm 307 mm

It is found where winters bring light frost. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 251 research-grade observations of Rhynchosia tomentosa that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.

This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one. Climate from CHELSA V2.1 (Karger et al. 2017); occurrences from 10.15468/dl.cgje2x.

Also published as 23 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.

  • Arcyphyllum erectum (Walter) Elliott
  • Dolicholus erectus (Walter) Vail
  • Dolicholus mollissimus (Elliott) Vail
  • Dolicholus tomentosus (L.) Vail
  • Glycine caroliniana Spreng.
  • Glycine erecta (Walter) Nutt.
  • Glycine mollissima Elliott
  • Glycine reniformis Pursh
  • Glycine tomentosa L.
  • Glycine tomentosa var. erecta (Walter) Michx.
  • Kennedynella tomentosa (L.) Steud.
  • Leptocyamus tomentosus (L.) Benth.
  • Phaseolus reniformis Eaton & Wright
  • Psoralea alopecurina Bertol.
  • Rhynchosia erecta (Walter) DC.
  • Rhynchosia intermedia (Torr. & A.Gray) Small
  • Rhynchosia mollissima (Elliott) Shuttlew. ex S.Watson
  • Rhynchosia mollissima (Elliott) G.Don
  • Rhynchosia simplicifolia var. intermedia (Torr. & A.Gray) F.J.Herm.
  • Rhynchosia tomentosa var. erecta (Walter) Torr. & A.Gray
  • Rhynchosia tomentosa var. intermedia Torr. & A.Gray
  • Rhynchosia volubilis Alph.Wood
  • Trifolium erectum Walter

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.