Juncus minutulus explained

Juncus minutulus is a species of rush (Juncaceae) informally^[1] referred to as minute rush, dwarf toad rush and annual rush.

Description

An annual, resembling and easily confused with a tiny Juncus bufonius with all parts smaller and with flowers rarely opening (cleistogamous): fruit capsule 2.5-3.0mm, stamens usually (2)3 instead of 6, anthers 1/4-1/3 x filaments (not 1/3-1 x), tepals usually shorter than 4mm, inner tepals acute (not long-tapering), 0-1(2) stem leaves, 1–3cm long.

J. bufonius also has cleistogamous forms that can very much resemble this in these features therefore all features should be examined carefully (such as inner tepal tip shape).^[2]

Range

Europe & North Asia, possibly cosmopolitan but reliable records are limited.^{[3] [4]}

Habitat

Similar to Juncus bufonius with which it may grow.

Turkey: Wet or temporarily wet, usually open soil, 0–1800 m.^[5]

Spain: Wet pastures or those in temporarily flooded places, on somewhat saline soils; 0-2900m ("Pastos húmedos o de lugares temporalmente inundados, en suelos algo salinos; 0-2900 m").^[6]

Istria

Wet roads, fields, ruderal regions.^[7]

Siberia: In wet lowlands, along banks of water reservoirs.^[8]

Further reading

• "The Juncus bufonius L. aggregate in western Europe", 1978 (Watsonia 12, 113-128), Cope, T.A. & Stace, C.A.
• "Revision of the Italian material of Juncus sect. Tenageia in the Herbarium Centrale Italicum: confirmations and novelties for Italy", 2022, Lorenzo Lastrucci, Valeria Gambirasio, Lorenzo Lazzaro, Daniele Viciani
• "The Revision of Juncus L. (Juncaceae) Genus in Central Anatolia, Turkey", 2015, Bülent Özbek.
• "The elusive Juncus minutulus: A failure to separate tetra- and hexaploid individuals of the Juncus bufonius complex in a morphometric comparison of cytometrically defined groups", 2011, Federick Rooks, Vlasta Jarolimova, Lenka Záveská Drábková, Jan Kirschner

Notes and References

1. Per Google search, a formal name is unknown
2. http://old.ibot.cas.cz/preslia/archive/Preslia_48_1976_329-339.pdf Juncus minutulus - přehlížený nový druh československé květeny, 1976, Josef Holub (in Czech and English)
3. https://archive.org/details/juncaceae30000unse/mode/2up Species Plantarum / Flora of the World / Part 8. Juncaceae 3: Juncus subg. Agathryon / compiled by Jan Kirschner
4. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77084798-1 Plants of the World Online (with map)
5. Book: Flora of Turkey and the East Aegean Islands, vol. 9 . Davis.
6. http://www.floraiberica.es/floraiberica/texto/pdfs/17_172_01_Juncus.pdf Flora iberica (in Spanish)
7. https://www.researchgate.net/publication/27189168 "The flora of Istria: Juncaceae", 2005, Karl-Georg Bernhardt, Mihaela Britvec
8. Flora of Siberia vol. 4, 2001 (English Translation)