Iris aphyllaL.

stool iris

WFO wfo-0000783074 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Iris aphylla, photographed by Aleksei Baushev
fig. a Aleksei Baushev, CC BY 4.0 / 2022-06-11 / obs. 205235332

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 14 botanical countries

Regions where Iris aphylla is native: Albania, Belarus, Bulgaria, Central European Russia, Czechia-Slovakia, France, Germany, Hungary, Italy, NW. Balkan Pen., Poland, Romania, South European Russia, Ukraine AlbaniaBelarusBulgariaCentral European RussiaCzechia-SlovakiaFranceGermanyHungaryItalyNW. Balkan Pen.PolandRomaniaSouth European RussiaUkraine
Native distribution of Iris aphylla, 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
Albania ALB EUROPE
Belarus BLR
Bulgaria BUL
Central European Russia RUC
Czechia-Slovakia CZE
France FRA
Germany GER
Hungary HUN
Italy ITA
NW. Balkan Pen. YUG
Poland POL
Romania ROM
South European Russia RUS
Ukraine UKR

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 59 in flower of 91 examined

Proportion of examined Iris aphylla 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 0 too few examined
Apr 3 4 too few examined
May 48 54 89% 78% to 95%
Jun 8 15 53% 30% to 75%
Jul 0 17 0% 0% to 18%
Aug 0 1 too few examined
Sep 0 0 too few examined
Oct 0 0 too few examined
Nov 0 0 too few examined
Dec 0 0 too few examined

Peak flowering in May. Each bar is the share of Iris aphylla 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. 59 of 91 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 2,017 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -13.2 °C -9.7 °C -5.6 °C
Warmest month, mean daily high 22.7 °C 23.9 °C 25.7 °C
Annual rainfall 503 mm 605 mm 693 mm
Rainfall in the driest quarter 79 mm 104 mm 135 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 2,017 research-grade observations of Iris aphylla 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 42 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.

  • Iris aphylla f. iulitae Pînzaru
  • Iris aphylla f. major (Zapał.) Soó
  • Iris aphylla subsp. bohemica (F.W.Schmidt) Dostál
  • Iris aphylla subsp. dacica (Beldie) Soó
  • Iris aphylla subsp. fieberi (Seidl) Dostál
  • Iris aphylla subsp. hungarica Waldst. & Kit.
  • Iris aphylla subsp. nudicaulis (Lam.) O.Schwarz
  • Iris aphylla subsp. polonica (Blocki ex Asch. & Graebn.) Soó
  • Iris aphylla var. hungarica (Waldst. & Kit.) D.Dubovik
  • Iris aphylla var. polonica Blocki ex Asch. & Graebn.
  • Iris biflora L.
  • Iris bifurca Steven ex Baker
  • Iris bisflorens Host
  • Iris bohemica F.W.Schmidt
  • Iris breviscapa Opiz
  • Iris clusiana Tausch
  • Iris dacica Beldie
  • Iris diantha C.Koch
  • Iris diantha K.Koch
  • Iris duerinckii Buckley
  • Iris extrafoliacea J.C.Mikan ex Pohl
  • Iris falcata Tausch
  • Iris fieberi Seidl
  • Iris furcata var. diantha (K.Koch) Grossh.

and 18 more.

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.