Platanthera unalascensis(Spreng.) Kurtz

slender-spire orchid

WFO wfo-0000274746 Accepted WFO 2026-06 8 photographs CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Platanthera unalascensis, photographed by Derek
fig. a Derek, CC BY 4.0 / 2021-07-15 / obs. 143953016

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
02632064
Filed as
Platanthera unalascensis (Spreng.) Kurtz
Det. by
R. K. Lauri 2014-08-02
Collected
N. H. Holmgren 1972-08-07
Origin
US
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. The holding institution does not serve this sheet’s image to third parties, so there is no photograph here. The record is real and the link goes to it. 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 herbarium sheets never recorded a determiner, which is ordinary.

Native range 20 botanical countries

Regions where Platanthera unalascensis is native: Alaska, Alberta, Aleutian Is., British Columbia, California, Colorado, Idaho, Mexico Northwest, Michigan, Montana, Nevada, New Mexico, Newfoundland, Ontario, Oregon, Québec, South Dakota, Utah, Washington, Wyoming AlaskaAlbertaBritish ColumbiaCaliforniaColoradoIdahoMexico NorthwestMichiganMontanaNevadaNew MexicoNewfoundlandOntarioOregonQuébecSouth DakotaUtahWashingtonWyoming
Native distribution of Platanthera unalascensis, 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
Alaska ASK NORTHERN AMERICA
Alberta ABT
Aleutian Is. ALU
British Columbia BRC
California CAL
Colorado COL
Idaho IDA
Mexico Northwest MXN
Michigan MIC
Montana MNT
Nevada NEV
New Mexico NWM
Newfoundland NFL
Ontario ONT
Oregon ORE
Québec QUE
South Dakota SDA
Utah UTA
Washington WAS
Wyoming WYO

Not drawn on the map: Aleutian Is.. We hold no public-domain boundary for this region, so it is listed rather than guessed at.

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 218 in flower of 273 examined

Proportion of examined Platanthera unalascensis in flower, by month
Month In flower Examined Share 95% interval
Jan 1 1 too few examined
Feb 0 1 too few examined
Mar 0 1 too few examined
Apr 2 3 too few examined
May 5 8 63% 31% to 86%
Jun 52 81 64% 53% to 74%
Jul 147 153 96% 92% to 98%
Aug 11 21 52% 32% to 72%
Sep 0 2 too few examined
Oct 0 1 too few examined
Nov 0 1 too few examined
Dec 0 0 too few examined

Peak flowering in Jul. Each bar is the share of Platanthera unalascensis 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. 218 of 273 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 8 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 1,635 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -15.3 °C -10.0 °C 2.8 °C
Warmest month, mean daily high 18.0 °C 23.3 °C 28.5 °C
Annual rainfall 480 mm 876 mm 1,998 mm
Rainfall in the driest quarter 36 mm 106 mm 251 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 1,635 research-grade observations of Platanthera unalascensis 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 14 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.

  • Habenaria foetida (Geyer ex Hook.) S.Watson
  • Habenaria schischmareffiana Cham.
  • Habenaria unalascensis (Spreng.) S.Watson
  • Habenaria unalaschensis (Spreng.) S.Watson
  • Herminium unalascense (Spreng.) Rchb.f.
  • Herminium unalaschensis (Spreng.) Rchb.f.
  • Monorchis unalaschcensis (Spreng.) O.Schwarz
  • Piperia unalascensis (Spreng.) Rydb.
  • Piperia unalascensis f. olympica P.M.Br.
  • Platanthera foetida Geyer ex Hook.
  • Platanthera schischmareffiana (Cham.) Lindl.
  • Platanthera unalaschcensis (Spreng.) Kurtz
  • Platanthera unalaschkensis Kraenzl.
  • Spiranthes unalascensis Spreng.

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 PIUN3. 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.