Astragalus purshii (woollypod milkvetch)

Plate 1 figs. a–h · 8 separate observations

Astragalus purshii, photographed by James M. Maley — fig. a James M. Maley, CC BY 4.0 / 2022-06-05 / obs. 204775149

Astragalus purshii, photographed by Shane Johnson — fig. b Shane Johnson, CC0 1.0 / obs. 204685884

Astragalus purshii, photographed by Garth Harwood — fig. g Garth Harwood, CC BY 4.0 / obs. 203092401

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 14 botanical countries

Native distribution of Astragalus purshii, 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
Alberta	ABT	NORTHERN AMERICA
British Columbia	BRC
California	CAL
Colorado	COL
Idaho	IDA
Montana	MNT
Nevada	NEV
North Dakota	NDA
Oregon	ORE
Saskatchewan	SAS
South Dakota	SDA
Utah	UTA
Washington	WAS
Wyoming	WYO

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 425 in flower of 775 examined

13%

82%

90%

43%

24%

29%

27%

Proportion of examined Astragalus purshii in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	1	8	13%	2% to 47%
Feb	0	10	0%	0% to 28%
Mar	62	76	82%	71% to 89%
Apr	222	246	90%	86% to 93%
May	106	247	43%	37% to 49%
Jun	23	96	24%	17% to 33%
Jul	5	61	8%	4% to 18%
Aug	0	7	0%	0% to 35%
Sep	2	7	29%	8% to 64%
Oct	4	15	27%	11% to 52%
Nov	0	1	too few examined
Dec	0	1	too few examined

Peak flowering in Apr. Each bar is the share of Astragalus purshii 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. 425 of 775 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 2 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 1,924 observations

Condition	5th percentile	Median	95th percentile
Coldest month, mean daily low	-11.8 °C	-6.4 °C	-2.4 °C
Warmest month, mean daily high	23.5 °C	28.8 °C	32.8 °C
Annual rainfall	187 mm	352 mm	815 mm
Rainfall in the driest quarter	18 mm	38 mm	83 mm

It is found where winters bring hard 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 1,924 research-grade observations of Astragalus purshii 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 44 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.

Astragalus allanaris E.Sheld.
Astragalus booneanus A.Nelson
Astragalus candelarius E.Sheld.
Astragalus candelarius var. exiguus E.Sheld.
Astragalus consectus E.Sheld.
Astragalus glareosus Douglas
Astragalus glareosus Hook.
Astragalus incurvus (Rydb.) Abrams
Astragalus inflexus var. glareosus (Douglas) M.E.Jones
Astragalus inflexus var. ordensis Jeps.
Astragalus jonesii Abrams
Astragalus lagopinus (Rydb.) M.Peck
Astragalus lanocarpus E.Sheld.
Astragalus lectulus S.Watson
Astragalus leucocystis Greene
Astragalus leucolobus subsp. consectus (E.Sheld.) Abrams
Astragalus ophiogenes Barneby
Astragalus purshii var. gavisus Jeps.
Astragalus purshii var. incurvus (Rydb.) Jeps.
Astragalus purshii var. interior M.E.Jones
Astragalus purshii var. longilobus M.E.Jones
Astragalus purshii var. ordensis (Jeps.) Jeps.
Astragalus purshii var. typicus Barneby
Astragalus ventosus Suksd. ex Rydb.

and 20 more.

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.
Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. 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.