Mentzelia albicaulis (whitestem blazingstar)

Plate 1 figs. a–h · 8 separate observations

Mentzelia albicaulis, photographed by Tim Messick — fig. a Tim Messick, CC BY 4.0 / 2022-04-21 / obs. 191133846

Mentzelia albicaulis, photographed by Kimball Garrett — fig. b Kimball Garrett, CC0 1.0 / obs. 187106236

Mentzelia albicaulis, photographed by Andrew Tree — fig. c Andrew Tree, CC BY 4.0 / obs. 186940505

Mentzelia albicaulis, photographed by Amy — fig. d Amy, CC BY 4.0 / obs. 182809836

Mentzelia albicaulis, photographed by Bobby McCabe — fig. e Bobby McCabe, CC BY 4.0 / obs. 135300039

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 18 botanical countries

Native distribution of Mentzelia albicaulis, 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
Arizona	ARI	NORTHERN AMERICA
British Columbia	BRC
California	CAL
Colorado	COL
Idaho	IDA
Mexico Northeast	MXE
Mexico Northwest	MXN
Montana	MNT
Nebraska	NEB
Nevada	NEV
New Mexico	NWM
Oregon	ORE
Saskatchewan	SAS
South Dakota	SDA
Texas	TEX
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 368 in flower of 394 examined

100%

98%

93%

92%

94%

89%

Proportion of examined Mentzelia albicaulis in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	12	12	100%	76% to 100%
Feb	43	44	98%	88% to 100%
Mar	157	169	93%	88% to 96%
Apr	85	92	92%	85% to 96%
May	49	52	94%	84% to 98%
Jun	16	18	89%	67% to 97%
Jul	2	2	too few examined
Aug	0	1	too few examined
Sep	0	0	too few examined
Oct	0	0	too few examined
Nov	1	1	too few examined
Dec	3	3	too few examined

Peak flowering in Jan. Each bar is the share of Mentzelia albicaulis 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. 368 of 394 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 6 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 1,556 observations

Condition	5th percentile	Median	95th percentile
Coldest month, mean daily low	-9.3 °C	-1.4 °C	8.3 °C
Warmest month, mean daily high	27.2 °C	33.1 °C	40.9 °C
Annual rainfall	111 mm	243 mm	482 mm
Rainfall in the driest quarter	7 mm	23 mm	63 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 1,556 research-grade observations of Mentzelia albicaulis 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 20 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.

Acrolasia albicaulis (Douglas ex Hook.) Rydb.
Acrolasia ctenophora (Rydb.) Rydb.
Acrolasia gracilis Rydb.
Acrolasia parviflora (A.Heller) A.Heller
Acrolasia tenerrima (Rydb.) Rydb.
Acrolasia tweedyi (Rydb.) Rydb.
Bartonia albicaulis Douglas ex Hook.
Mentzelia albicaulis var. ctenophora (Rydb.) J.Darl.
Mentzelia albicaulis var. genuina Urb. & Gilg
Mentzelia albicaulis var. gracilis (Rydb.) J.Darl.
Mentzelia albicaulis var. spectabilis M.E.Jones
Mentzelia albicaulis var. tenerrima (Rydb.) H.St.John
Mentzelia ctenophora Rydb.
Mentzelia gracilis (Rydb.) H.J.Thomps. & F.H.Lewis
Mentzelia mojavensis H.J.Thomps. & J.E.Roberts
Mentzelia parviflora A.Heller
Mentzelia tenerrima Rydb.
Mentzelia tweedyi Rydb.
Trachyphytum albicaule Nutt. ex Torr. & A.Gray
Trachyphytum gracile Nutt. ex Torr. & 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.