Nabalus alatus (western rattlesnakeroot)

Plate 1 figs. a–h · 8 separate observations

Nabalus alatus, photographed by Ellyne Geurts — fig. a Ellyne Geurts, CC0 1.0 / 2021-08-19 / obs. 166744511

Nabalus alatus, photographed by Nolan Exe — fig. c Nolan Exe, CC BY 4.0 / obs. 144158303

Nabalus alatus, photographed by Randal — fig. d Randal, CC0 1.0 / obs. 143312559

Nabalus alatus, photographed by rappman — fig. e rappman, CC BY 4.0 / obs. 47065888

Nabalus alatus, photographed by naokitakebayashi — fig. f naokitakebayashi, CC BY-SA 4.0 / obs. 44889637

Nabalus alatus, photographed by Connie Taylor — fig. g Connie Taylor, CC BY 4.0 / obs. 24036116

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 8 botanical countries

Native distribution of Nabalus alatus, 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.

Region	TDWG code	Continent
Alaska	ASK	NORTHERN AMERICA
Alberta	ABT
Aleutian Is.	ALU
British Columbia	BRC
Idaho	IDA
Montana	MNT
Oregon	ORE
Washington	WAS

Not drawn on the map: Aleutian Is.. We hold no public-domain boundary for this region, so it is listed rather than guessed at.

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 33 in flower of 54 examined

59%

83%

60%

Proportion of examined Nabalus alatus 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	1	too few examined
Apr	0	0	too few examined
May	0	2	too few examined
Jun	0	3	too few examined
Jul	10	17	59%	36% to 78%
Aug	20	24	83%	64% to 93%
Sep	3	5	60%	23% to 88%
Oct	0	1	too few examined
Nov	0	1	too few examined
Dec	0	0	too few examined

Peak flowering in Aug. Each bar is the share of Nabalus alatus 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. 33 of 54 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 8 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.

Cacalia acuminata Fisch. ex Herder
Mulgedium hastatum Less.
Nabalus hastatus (Less.) A.Heller
Prenanthes alata (Hook.) D.Dietr.
Prenanthes alata var. alata
Prenanthes hastata A.Nelson & J.F.Macbr.
Prenanthes lessingii Hultén
Sonchus hastatus Less.

Sourcesevery claim on this page

World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
USDA PLANTS Database. common name, checklist symbol PRAL. public domain. Retrieved 2026-07-13.
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.