Senecio flaccidusLess.

threadleaf ragwort

WFO wfo-0000014246 Accepted WFO 2026-06 8 photographs CC BY

Plate 1 figs. a–h · 8 separate observations

Senecio flaccidus, photographed by Madeleine Claire
fig. a Madeleine Claire, CC BY 4.0 / 2022-06-04 / obs. 203603364

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.

The specimen a real sheet, in a real collection

Herbarium
The New York Botanical Garden
Accession
427169
Filed as
Senecio flaccidus var. flaccidus
Det. by
T. M. Barkley 1998-01-01
Collected
not recorded
Origin
MX
The sheet
View the digitised specimen (CC BY 4.0)

A real pressed plant, in a real collection, under the accession number above. Not an illustration of one. We link to the digitised sheet rather than rehosting it, because the holding institutions do not serve their images to third parties reliably and we are not going to show you a picture we cannot actually deliver. Where we hold no openly licensed sheet for a species this section is simply absent, and where a sheet never recorded who determined it, that field stays empty rather than being filled in. Roughly half of all sheets never recorded a determiner, which is ordinary.

Native range 14 botanical countries

Regions where Senecio flaccidus is native: Arizona, California, Colorado, Kansas, Mexico Central, Mexico Gulf, Mexico Northeast, Mexico Northwest, Mexico Southwest, Nevada, New Mexico, Oklahoma, Texas, Utah ArizonaCaliforniaColoradoKansasMexico CentralMexico GulfMexico NortheastMexico NorthwestMexico SouthwestNevadaNew MexicoOklahomaTexasUtah
Native distribution of Senecio flaccidus, 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
Arizona ARI NORTHERN AMERICA
California CAL
Colorado COL
Kansas KAN
Mexico Central MXC
Mexico Gulf MXG
Mexico Northeast MXE
Mexico Northwest MXN
Mexico Southwest MXS
Nevada NEV
New Mexico NWM
Oklahoma OKL
Texas TEX
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 621 in flower of 666 examined

Proportion of examined Senecio flaccidus in flower, by month
Month In flower Examined Share 95% interval
Jan 20 26 77% 58% to 89%
Feb 7 11 64% 35% to 85%
Mar 26 29 90% 74% to 96%
Apr 116 120 97% 92% to 99%
May 105 109 96% 91% to 99%
Jun 57 64 89% 79% to 95%
Jul 19 19 100% 83% to 100%
Aug 32 34 94% 81% to 98%
Sep 53 58 91% 81% to 96%
Oct 96 97 99% 94% to 100%
Nov 72 78 92% 84% to 96%
Dec 18 21 86% 65% to 95%

Peak flowering in Jul. Each bar is the share of Senecio flaccidus 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. 621 of 666 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 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 2,005 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -6.1 °C 1.1 °C 5.7 °C
Warmest month, mean daily high 28.1 °C 32.5 °C 37.0 °C
Annual rainfall 188 mm 400 mm 603 mm
Rainfall in the driest quarter 5 mm 31 mm 64 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 2,005 research-grade observations of Senecio flaccidus 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.

  • Senecio douglasii DC.
  • Senecio douglasii subsp. douglasii
  • Senecio douglasii subsp. longilobus (Benth.) W.A.Weber
  • Senecio douglasii var. douglasii
  • Senecio douglasii var. jamesii (Torr. & A.Gray) Ediger ex Correll & M.C.Johnst.
  • Senecio douglasii var. longilobus (Benth.) L.D.Benson
  • Senecio douglasii var. monoensis (Greene) Jeps.
  • Senecio douglasii var. tularensis Munz
  • Senecio durangensis Groenman
  • Senecio durangensis var. atrapiculatus T.M.Barkley
  • Senecio filicifolius Greenm.
  • Senecio filifolius Nutt.
  • Senecio filifolius var. filifolius
  • Senecio flaccidus var. flaccidus
  • Senecio lathyroides Greene
  • Senecio longilobus Benth.
  • Senecio monoensis Greene
  • Senecio pectinatus A.Nelson

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. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. 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.