Ambrosia dumosa (White Burrobush)

Plate 1 figs. a–h · 8 separate observations

Ambrosia dumosa, photographed by Bobby McCabe — fig. a Bobby McCabe, CC BY 4.0 / 2022-05-02 / obs. 193818557

Ambrosia dumosa, photographed by Tim Messick — fig. e Tim Messick, CC BY 4.0 / obs. 191127349

Ambrosia dumosa, photographed by paulexcoff — fig. g paulexcoff, CC BY-SA 4.0 / obs. 189369034

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 5 botanical countries

Native distribution of Ambrosia dumosa, 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
California	CAL
Mexico Northwest	MXN
Nevada	NEV
Utah	UTA

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 535 in flower of 1,525 examined

23%

49%

55%

33%

19%

49%

36%

29%

Proportion of examined Ambrosia dumosa in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	21	250	8%	6% to 13%
Feb	47	206	23%	18% to 29%
Mar	182	369	49%	44% to 54%
Apr	141	255	55%	49% to 61%
May	23	69	33%	23% to 45%
Jun	1	17	6%	1% to 27%
Jul	0	6	0%	0% to 39%
Aug	1	3	too few examined
Sep	7	36	19%	10% to 35%
Oct	38	78	49%	38% to 60%
Nov	32	89	36%	27% to 46%
Dec	42	147	29%	22% to 36%

Peak flowering in Apr. Each bar is the share of Ambrosia dumosa 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. 535 of 1,525 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. One month has fewer than 5 examined observations, so no proportion is drawn for it. 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 4 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.

Franseria albicaulis Torr.
Franseria dumosa A.Gray
Franseria dumosa var. dumosa
Gaertneria dumosa (A.Gray) Kuntze

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.