Trillium sessileL.

toadshade

WFO wfo-0000750817 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h

Trillium sessile, photographed by Sarah Culliton
fig. a Sarah Culliton, CC BY 4.0 / 2022-05-28 / obs. 201734991
Trillium sessile, photographed by Alby Penney
fig. b Alby Penney, CC0 1.0 / obs. 197464546
Trillium sessile, photographed by Fluff Berger
fig. c Fluff Berger, CC BY-SA 4.0 / obs. 194436779
Trillium sessile, photographed by Katie Kucera
fig. d Katie Kucera, CC BY 4.0 / obs. 197613712
Trillium sessile, photographed by Kristen Diesburg
fig. e Kristen Diesburg, CC BY 4.0 / obs. 196067750
Trillium sessile, photographed by Rebecca Gimenez Husted
fig. f Rebecca Gimenez Husted, CC BY 4.0 / obs. 193814016
Trillium sessile, photographed by Terri Koontz
fig. g Terri Koontz, CC0 1.0 / obs. 196864690
Trillium sessile, photographed by Craig Martin
fig. h Craig Martin, CC0 1.0 / obs. 195451789

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.

Confused withby our own model

These are not lookalikes we guessed at. Each one is a species our identification model genuinely mistook for this plant, and how many times. The error rate is published.

Flowering n = 3,316 observations

Peak flowering in Apr, from 3,316 community-annotated observations worldwide. This is a global aggregate, not a forecast for your garden: the same species flowers on different dates in different hemispheres, and citizen-science records cluster near cities, at weekends, and in spring. Where a species has fewer than 30 annotated records we do not draw this chart at all.

Also published as 10 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.

  • Esdra sessilis (L.) Salisb.
  • Phyllantherum sessile (L.) Nieuwl.
  • Trillium isanthum Raf.
  • Trillium longiflorum Raf.
  • Trillium membranaceum Raf.
  • Trillium rotundifolium Raf.
  • Trillium sessile f. sessile
  • Trillium sessile f. viridiflorum Beyer
  • Trillium sessile var. boreale Nutt.
  • Trillium tinctorium Raf.

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.

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