Senna armata (desertsenna)

Plate 1 figs. a–h · 8 separate observations

Senna armata, photographed by Bobby McCabe — fig. a Bobby McCabe, CC BY 4.0 / 2022-04-30 / obs. 192569459

Senna armata, photographed by Alix Kosmala — fig. b Alix Kosmala, CC BY 4.0 / obs. 190764114

Senna armata, photographed by Tim Messick — fig. c Tim Messick, CC BY 4.0 / obs. 191472727

Senna armata, photographed by paulexcoff — fig. e paulexcoff, CC BY-SA 4.0 / obs. 189369013

Senna armata, photographed by ant, like the bug — fig. f ant, like the bug, CC0 1.0 / obs. 188405333

Senna armata, photographed by Diego Blanco — fig. g Diego Blanco, CC0 1.0 / obs. 175968019

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 4 botanical countries

Native distribution of Senna armata, 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

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 320 in flower of 488 examined

27%

59%

89%

91%

58%

70%

38%

60%

29%

48%

Proportion of examined Senna armata in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	2	22	9%	3% to 28%
Feb	11	41	27%	16% to 42%
Mar	51	86	59%	49% to 69%
Apr	109	122	89%	83% to 94%
May	86	95	91%	83% to 95%
Jun	7	12	58%	32% to 81%
Jul	0	2	too few examined
Aug	7	10	70%	40% to 89%
Sep	5	13	38%	18% to 64%
Oct	21	35	60%	44% to 74%
Nov	5	17	29%	13% to 53%
Dec	16	33	48%	33% to 65%

Peak flowering in May. Each bar is the share of Senna armata 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. 320 of 488 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.

Where it actually grows measured, from 1,537 observations

Condition	5th percentile	Median	95th percentile
Coldest month, mean daily low	1.6 °C	4.1 °C	8.5 °C
Warmest month, mean daily high	34.6 °C	37.3 °C	40.0 °C
Annual rainfall	108 mm	133 mm	278 mm
Rainfall in the driest quarter	5 mm	8 mm	18 mm

It is found where winters are cool but frost is light or absent. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 1,537 research-grade observations of Senna armata 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 2 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.

Cassia armata S.Watson
Xerocassia armata (S.Watson) Britton & Rose

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.