Juncus acutusL.

Plate 1 figs. a–h · 8 separate observations

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

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 55 botanical countries

Not drawn on the map: Great Britain, Juan Fernández Is.. We hold no public-domain boundary for these regions, so they are 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 53 in flower of 522 examined

Peak flowering in Oct. Each bar is the share of Juncus acutus 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. 53 of 522 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 2,040 observations

It is found where winters are cool but frost is light or absent. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 2,040 research-grade observations of Juncus acutus 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 24 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.

• Juncus acutus f. xanthosus Jeps.
• Juncus acutus subsp. decompositus (Guss.) Arcang.
• Juncus acutus subsp. multibracteatus (Tineo) K.Richt.
• Juncus acutus subsp. variegatus (Caruel) Nyman
• Juncus acutus unranked megalocarpus Asch. & Graebn.
• Juncus acutus var. conglobatus Trautv.
• Juncus acutus var. conglomeratus Buchenau
• Juncus acutus var. decompositus Guss.
• Juncus acutus var. effusus Buchenau
• Juncus acutus var. leopoldii (Parl.) Buchenau
• Juncus acutus var. longibracteatus Buchenau
• Juncus acutus var. multibracteatus (Tineo) Pérez Lara
• Juncus acutus var. multibracteatus (Tineo) Cout.
• Juncus acutus var. paniculatus Cout.
• Juncus acutus var. sphaerocarpus Engelm.
• Juncus acutus var. xanthosus Jeps.
• Juncus karelinii Steud.
• Juncus leopoldii Parl.
• Juncus macrocarpus Nees
• Juncus maritimus subsp. acutus (L.) Douin
• Juncus multibracteatus Tineo
• Juncus robustus S.Watson
• Juncus spinosus Forssk.
• Juncus variegatus Caruel

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.