Ditaxis serrata (California silverbush)

Plate 1 figs. a–h · 8 separate observations

Ditaxis serrata, photographed by Bobby McCabe — fig. a Bobby McCabe, CC BY 4.0 / 2022-04-30 / obs. 192562861

Ditaxis serrata, photographed by nmoorhatch — fig. c nmoorhatch, CC BY 4.0 / obs. 182112860

Ditaxis serrata, photographed by Sam Kieschnick — fig. d Sam Kieschnick, CC BY 4.0 / obs. 109811811

Ditaxis serrata, photographed by Jesse Rorabaugh — fig. e Jesse Rorabaugh, CC0 1.0 / obs. 64259536

Ditaxis serrata, photographed by Cleveland Powell — fig. f Cleveland Powell, CC BY 4.0 / obs. 41588188

Ditaxis serrata, photographed by Bob Miller — fig. g Bob Miller, CC BY 4.0 / obs. 30818048

Ditaxis serrata, photographed by Eliseo D Moreno — fig. h Eliseo D Moreno, CC BY-SA 4.0 / obs. 29457321

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 13 botanical countries

Native distribution of Ditaxis serrata, 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 Central	MXC
Mexico Gulf	MXG
Mexico Northeast	MXE
Mexico Northwest	MXN
Mexico Southeast	MXT
Mexico Southwest	MXS
Nevada	NEV
New Mexico	NWM
Texas	TEX
Guatemala	GUA	SOUTHERN AMERICA
Nicaragua	NIC

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 182 in flower of 205 examined

81%

95%

93%

100%

80%

82%

90%

79%

90%

Proportion of examined Ditaxis serrata in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	26	32	81%	65% to 91%
Feb	37	39	95%	83% to 99%
Mar	14	15	93%	70% to 99%
Apr	9	9	100%	70% to 100%
May	9	9	100%	70% to 100%
Jun	2	2	too few examined
Jul	5	5	100%	57% to 100%
Aug	4	5	80%	38% to 96%
Sep	9	11	82%	52% to 95%
Oct	19	21	90%	71% to 97%
Nov	22	28	79%	60% to 90%
Dec	26	29	90%	74% to 96%

Peak flowering in Apr. Each bar is the share of Ditaxis serrata 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. 182 of 205 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 665 observations

Condition	5th percentile	Median	95th percentile
Coldest month, mean daily low	2.9 °C	5.9 °C	12.2 °C
Warmest month, mean daily high	33.6 °C	39.2 °C	41.9 °C
Annual rainfall	92 mm	217 mm	418 mm
Rainfall in the driest quarter	3 mm	12 mm	28 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 665 research-grade observations of Ditaxis serrata 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 18 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.

Aphora serrata Torr.
Argythamnia californica Brandegee
Argythamnia dressleriana J.W.Ingram
Argythamnia gracilis Brandegee
Argythamnia micrandra Croizat
Argythamnia neomexicana Müll.Arg.
Argythamnia serrata Brandegee
Argythamnia serrata (Torr.) Müll.Arg.
Argythamnia serrata var. magdalenae Millsp.
Ditaxis californica (Brandegee) A.Heller
Ditaxis dressleriana (J.W.Ingram) Radcl.-Sm. & Govaerts
Ditaxis gracilis Rose & Standl.
Ditaxis micrandra (Croizat) Radcl.-Sm. & Govaerts
Ditaxis neomexicana (Müll.Arg.) A.Heller
Ditaxis odontophylla Rose & Standl.
Ditaxis serrata var. californica (Brandegee) V.W.Steinm. & Felger
Ditaxis serrata var. magdalenae (Millsp.) Eastw.
Ditaxis serrata var. serrata

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.
USDA PLANTS Database. common name, checklist symbol ARCA19. public domain. 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.