Hebecarpa barbeyana (blue milkwort)

Plate 1 figs. a–h · 8 separate observations

Hebecarpa barbeyana, photographed by Dominic Gentilcore — fig. a Dominic Gentilcore, CC BY 4.0 / 2021-07-27 / obs. 148225459

Hebecarpa barbeyana, photographed by Leticia Jiménez Hernández — fig. b Leticia Jiménez Hernández, CC BY-SA 4.0 / obs. 136999743

Hebecarpa barbeyana, photographed by Francisco Martínez González — fig. f Francisco Martínez González, CC BY-SA 4.0 / obs. 70449694

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 8 botanical countries

Native distribution of Hebecarpa barbeyana, 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
Mexico Central	MXC
Mexico Gulf	MXG
Mexico Northeast	MXE
Mexico Northwest	MXN
Mexico Southwest	MXS
New Mexico	NWM
Texas	TEX

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.

Where it actually grows measured, from 165 observations

Condition	5th percentile	Median	95th percentile
Coldest month, mean daily low	-2.9 °C	0.6 °C	7.3 °C
Warmest month, mean daily high	26.3 °C	31.5 °C	34.8 °C
Annual rainfall	278 mm	414 mm	622 mm
Rainfall in the driest quarter	25 mm	37 mm	65 mm

It is found where winters bring light 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 165 research-grade observations of Hebecarpa barbeyana 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.

Also published as 8 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.

Polygala barbeyana Chodat
Polygala intricata S.F.Blake
Polygala longa S.F.Blake
Polygala racemosa S.F.Blake
Polygala reducta S.F.Blake
Polygala scopulorum Brandegee
Polygala tenuiloba S.F.Blake
Polygala zacatecana S.F.Blake

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 POBA. 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.