Halenia deflexa(Sm.) Griseb.

American spurred gentian

WFO wfo-0001063148 Accepted WFO 2026-06 8 photographs CC0 / CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Halenia deflexa, photographed by Henry "Nick" Robertson
fig. a Henry "Nick" Robertson, CC BY-SA 4.0 / 2021-11-06 / obs. 167771963

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 23 botanical countries

Regions where Halenia deflexa is native: Alberta, British Columbia, Labrador, Maine, Manitoba, Massachusetts, Michigan, Minnesota, Montana, New Brunswick, New Hampshire, New York, Newfoundland, North Dakota, Northwest Territories, Nova Scotia, Ontario, Québec, Saskatchewan, South Dakota, Vermont, Wisconsin, Wyoming AlbertaBritish ColumbiaLabradorMaineManitobaMassachusettsMichiganMinnesotaMontanaNew BrunswickNew HampshireNew YorkNewfoundlandNorth DakotaNorthwest TerritoriesNova ScotiaOntarioQuébecSaskatchewanSouth DakotaVermontWisconsinWyoming
Native distribution of Halenia deflexa, 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
British Columbia BRC
Labrador LAB
Maine MAI
Manitoba MAN
Massachusetts MAS
Michigan MIC
Minnesota MIN
Montana MNT
New Brunswick NBR
New Hampshire NWH
New York NWY
Newfoundland NFL
North Dakota NDA
Northwest Territories NWT
Nova Scotia NSC
Ontario ONT
Québec QUE
Saskatchewan SAS
South Dakota SDA
Vermont VER
Wisconsin WIS
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.

Flowering 63 in flower of 95 examined

Proportion of examined Halenia deflexa in flower, by month
Month In flower Examined Share 95% interval
Jan 0 0 too few examined
Feb 0 0 too few examined
Mar 0 1 too few examined
Apr 0 0 too few examined
May 0 0 too few examined
Jun 0 1 too few examined
Jul 26 33 79% 62% to 89%
Aug 33 49 67% 53% to 79%
Sep 4 10 40% 17% to 69%
Oct 0 1 too few examined
Nov 0 0 too few examined
Dec 0 0 too few examined

Peak flowering in Jul. Each bar is the share of Halenia deflexa 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. 63 of 95 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 9 months have fewer than 5 examined observations, so no proportion is drawn for them. 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 1,090 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -19.6 °C -14.5 °C -9.2 °C
Warmest month, mean daily high 19.7 °C 22.9 °C 25.6 °C
Annual rainfall 492 mm 822 mm 1,238 mm
Rainfall in the driest quarter 53 mm 120 mm 247 mm

It is found where winters are severely cold. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 1,090 research-grade observations of Halenia deflexa 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.

  • Halenia brentoniana Griseb.
  • Halenia corniculata subsp. deflexa (Sm.) Hultén
  • Halenia deflexa f. deflexa
  • Halenia deflexa f. heterantha (Fernald) Fernald
  • Halenia deflexa subsp. brentoniana (Griseb.) J.M.Gillett
  • Halenia deflexa var. brentoniana (Griseb.) A.Gray
  • Halenia deflexa var. deflexa
  • Halenia deflexa var. heterantha Fernald
  • Halenia heterantha Griseb.
  • Halenia michauxiana G.Don
  • Swertia americana Spreng.
  • Swertia deflexa Sm.
  • Swertia michauxiana Schult.
  • Tetragonanthus brentonianus (Griseb.) A.Heller
  • Tetragonanthus deflexus (Sm.) Kuntze
  • Tetragonanthus deflexus var. brentonianus (Griseb.) Britton
  • Tetragonanthus deflexus var. heteranthus (Griseb.) Britton
  • Tetragonanthus heterantha (Griseb.) A.Heller

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.