Cardamine douglassiiBritton

Purple Cress

WFO wfo-0000586725 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h

Cardamine douglassii, photographed by Skyler Principe
fig. a Skyler Principe, CC BY 4.0 / 2022-05-06 / obs. 203904906
Cardamine douglassii, photographed by scapularis
fig. b scapularis, CC BY 4.0 / obs. 192419021
Cardamine douglassii, photographed by Alexis Williams
fig. c Alexis Williams, CC BY 4.0 / obs. 196160474
Cardamine douglassii, photographed by Patrick Hanly
fig. d Patrick Hanly, CC BY 4.0 / obs. 190309844
Cardamine douglassii, photographed by Patrick Hanly
fig. e Patrick Hanly, CC BY 4.0 / obs. 191843608
Cardamine douglassii, photographed by Yann Kemper
fig. f Yann Kemper, CC0 1.0 / obs. 192540786
Cardamine douglassii, photographed by Howard Williams
fig. g Howard Williams, CC BY-SA 4.0 / obs. 189284226
Cardamine douglassii, photographed by Howard Williams
fig. h Howard Williams, CC BY-SA 4.0 / obs. 187756125

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.

Flowering n = 1,559 observations

Peak flowering in Apr, from 1,559 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 6 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.

  • Arabis douglassii Torr.
  • Arabis rhomboidea var. purpurea Torr.
  • Cardamine rhomboidea var. purpurea (Torr.) Torr.
  • Dentaria douglasii (Britton) Greene
  • Dracamine purpurea Nieuwl.
  • Thlaspi tuberosum Nutt.

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.