Juncus is a genus of , commonly known as rushes. It is the largest genus in the family Juncaceae,[
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Description
Rushes of the genus Juncus are herbaceous plant plants that superficially resemble Poaceae or .
The form of the flower differentiates rushes from grasses or sedges. The flowers of Juncus comprise five whorls of floral parts: three sepals, three petals (or, taken together, six tepals), two to six (in two whorls) and a stigma with three lobes.
In Juncus section Juncotypus (formerly called Juncus subg. Genuini),
Distribution and ecology
Juncus has a cosmopolitan distribution, with species found throughout the world, with the exception of Antarctica.
Fossil record
Several fossil fruits of a Juncus species have been described from middle Miocene strata of the Fasterholt area near Silkeborg in Central Jutland, Denmark.[Angiosperm Fruits and Seeds from the Middle Miocene of Jutland (Denmark) by Else Marie Friis, The Royal Danish Academy of Sciences and Letters 24:3, 1985]
Classification
The genus Juncus was first named by Carl Linnaeus in his 1753 Species Plantarum. The type species of the genus was designated by Frederick Vernon Coville, who in 1913 chose the first species in Linnaeus' account, Juncus acutus.
In 2013 the genus Oreojuncus was separated from Juncus. In 2022 Viktorie Brožová et al. published a phylogenetic analysis of the cyperids (families Juncaceae, Cyperaceae, and Thurniaceae) which found Juncus to be paraphyletic, and the authors proposed that six new genera, Alpinojuncus, Agathryon, Australojuncus, Boreojuncus, Juncinella, and Verojuncus, be split from Juncus.[Viktorie Brožová, Jarosław Proćków, Lenka Záveská Drábková, Toward finally unraveling the phylogenetic relationships of Juncaceae with respect to another cyperid family, Cyperaceae. Molecular Phylogenetics and Evolution
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/ref> As of July 2025 Plants of the World Online accepts Juncinella but treats the others as synonyms of Juncus.[
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The genus is divided into the following subgenus and sections:
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Juncus subg. Juncus
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sect. Juncus
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sect. Graminei (Engelm.) Engelm.
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sect. Caespitosi Cout.
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sect. Stygiopsis Kuntze
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sect. Ozophyllum Dumort.
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sect. Iridifolii Snogerup & Kirschner
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Juncus subg. Poiophylli Buchenau
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sect. Tenageia Dumort.
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sect. Steirochloa Griseb.
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sect. Juncotypus Dumort.
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sect. Forskalina Kuntze
Species
As of July 2025, Plants of the World Online accepts 342 species:[
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Formerly placed here
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Juncinella capitata (as Juncus capitatus Weigel)
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Juncinella cephalotes (as Juncus cephalotes Thunb.)
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Juncinella obliqua (as Juncus obliquus Adamson)
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Juncinella picta (as Juncus pictus Steud.)
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Juncinella rupestris (as Juncus rupestris Kunth)
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Juncinella scabriuscula (as Juncus scabriusculus Kunth)
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Juncinella stenopetala (as Juncus stenopetalus Adamson)
