Xanthisma grindelioides(Nutt.) D.R.Morgan & R.L.Hartm.

rayless tansyaster

WFO wfo-0000019031 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Xanthisma grindelioides, photographed by Bobby McCabe
fig. a Bobby McCabe, CC BY 4.0 / 2021-08-18 / obs. 151706377
Xanthisma grindelioides, photographed by John Brew
fig. b John Brew, CC BY 4.0 / obs. 109431186
Xanthisma grindelioides, photographed by Matt Berger
fig. c Matt Berger, CC BY 4.0 / obs. 83086421
Xanthisma grindelioides, photographed by Julien Tchilinguirian
fig. d Julien Tchilinguirian, CC BY 4.0 / obs. 47424990
Xanthisma grindelioides, photographed by Matt Lavin
fig. e Matt Lavin, CC BY 4.0 / obs. 171182551
Xanthisma grindelioides, photographed by John Gaskin
fig. f John Gaskin, CC0 1.0 / obs. 181367013
Xanthisma grindelioides, photographed by Matt Berger
fig. g Matt Berger, CC BY 4.0 / obs. 141571835
Xanthisma grindelioides, photographed by Matt Berger
fig. h Matt Berger, CC BY 4.0 / obs. 141571958

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

Regions where Xanthisma grindelioides is native: Alberta, Arizona, Colorado, Idaho, Montana, Nebraska, Nevada, New Mexico, North Dakota, Saskatchewan, South Dakota, Utah, Wyoming AlbertaArizonaColoradoIdahoMontanaNebraskaNevadaNew MexicoNorth DakotaSaskatchewanSouth DakotaUtahWyoming
Native distribution of Xanthisma grindelioides, 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.
RegionTDWG codeContinent
Alberta ABT NORTHERN AMERICA
Arizona ARI
Colorado COL
Idaho IDA
Montana MNT
Nebraska NEB
Nevada NEV
New Mexico NWM
North Dakota NDA
Saskatchewan SAS
South Dakota SDA
Utah UTA
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.

Where it actually grows measured, from 269 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -13.8 °C -10.5 °C -6.1 °C
Warmest month, mean daily high 25.3 °C 27.1 °C 32.7 °C
Annual rainfall 216 mm 312 mm 427 mm
Rainfall in the driest quarter 30 mm 40 mm 70 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 269 research-grade observations of Xanthisma grindelioides 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 9 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.

  • Aster nuttallii (Torr. & A.Gray) Kuntze
  • Eriocarpum grindelioides Nutt.
  • Haplopappus nuttallii Torr. & A.Gray
  • Haplopappus nuttallii var. depressus Maguire
  • Machaeranthera grindelioides (Nutt.) Shinners
  • Machaeranthera grindelioides var. depressa (Maguire) Cronquist & D.D.Keck
  • Machaeranthera grindelioides var. grindelioides
  • Sideranthus grindelioides (Nutt.) Britton
  • Sideranthus grindelioides (Nutt.) Britton ex Rydb.

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. USDA PLANTS Database. common name, checklist symbol MAGR2. public domain. Retrieved 2026-07-13.
  4. 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.