Lewisia pygmaea (alpine lewisia)

Plate 1 figs. a–h · 8 separate observations

Lewisia pygmaea, photographed by Martin Purdy — fig. a Martin Purdy, CC BY 4.0 / 2020-07-27 / obs. 98852796

Lewisia pygmaea, photographed by Adam J. Searcy — fig. d Adam J. Searcy, CC BY 4.0 / obs. 99006710

Lewisia pygmaea, photographed by Jim Morefield — fig. f Jim Morefield, CC BY 4.0 / obs. 174375060

Lewisia pygmaea, photographed by Steve Matson — fig. h Steve Matson, CC BY 4.0 / obs. 120885218

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 Lewisia pygmaea, 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
Arizona	ARI
British Columbia	BRC
California	CAL
Colorado	COL
Idaho	IDA
Montana	MNT
Nevada	NEV
New Mexico	NWM
Oregon	ORE
Utah	UTA
Washington	WAS
Wyoming	WYO
Yukon	YUK

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 136 in flower of 146 examined

100%

96%

93%

80%

Proportion of examined Lewisia pygmaea 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	0	too few examined
Apr	0	0	too few examined
May	11	11	100%	74% to 100%
Jun	49	51	96%	87% to 99%
Jul	67	72	93%	85% to 97%
Aug	8	10	80%	49% to 94%
Sep	1	2	too few examined
Oct	0	0	too few examined
Nov	0	0	too few examined
Dec	0	0	too few examined

Peak flowering in May. Each bar is the share of Lewisia pygmaea 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. 136 of 146 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 8 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 1,056 observations

Condition	5th percentile	Median	95th percentile
Coldest month, mean daily low	-21.0 °C	-16.9 °C	-9.7 °C
Warmest month, mean daily high	16.2 °C	19.4 °C	24.3 °C
Annual rainfall	508 mm	913 mm	1,369 mm
Rainfall in the driest quarter	72 mm	150 mm	256 mm

It is found where winters are severely cold. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 1,056 research-grade observations of Lewisia pygmaea 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 16 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.

Calandrinia grayi Britton
Lewisia exarticulata H.St.John
Lewisia glandulosa (Rydb.) Dempster
Lewisia minima A.Nelson
Lewisia pygmaea subsp. glandulosa (Rydb.) Ferris
Lewisia pygmaea subsp. pygmaea
Lewisia pygmaea var. aridorum Bartlett
Lewisia pygmaea var. pygmaea
Lewisia sierrae Ferris
Oreobroma aridorum A.Heller
Oreobroma exarticulatum (H.St.John) Rydb.
Oreobroma glandulosum Rydb.
Oreobroma grayi (Britton) Rydb.
Oreobroma minimum A.Nelson
Oreobroma pygmaeum (A.Gray) Howell
Talinum pygmaeum A.Gray

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.