Hydrophyllum capitatumDouglas ex Benth.

ballhead waterleaf

WFO wfo-0001066615 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h

Hydrophyllum capitatum, photographed by Cecelia Alexander
fig. a Cecelia Alexander, CC0 1.0 / 2022-06-06 / obs. 204010738

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 = 1,100 observations

Flowering observations of Hydrophyllum capitatum by month
MonthObservations
Jan0
Feb0
Mar36
Apr347
May421
Jun247
Jul48
Aug1
Sep0
Oct0
Nov0
Dec0

Peak flowering in May, from 1,100 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 3 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.

  • Hydrophyllum capitatum subvar. laxum Brand
  • Hydrophyllum capitatum var. capitatum
  • Hydrophyllum thompsonii Peck

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.