Juncus is a genus of monocotyledonous flowering plants, commonly known as rushes. It is the largest genus in the family Juncaceae, containing around 340 species.
Description Rushes of the genus Juncus are herbaceous plants that superficially resemble grasses or sedges. They have historically received little attention from botanists; in his 1819 monograph, James Ebenezer Bicheno described the genus as "obscure and uninviting".
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 stamens (in two whorls) and a stigma with three lobes. The stems are round in cross-section, unlike those of sedges, which are typically somewhat triangular in cross-section.
In Juncus section Juncotypus (formerly called Juncus subg. Genuini), which contains some of the most widespread and familiar species, the leaves are reduced to sheaths around the base of the stem and the bract subtending the inflorescence closely resembles a continuation of the stem, giving the appearance that the inflorescence is lateral.
Distribution and ecology Juncus has a cosmopolitan distribution, with species found throughout the world, with the exception of Antarctica. They typically grow in cold or wet habitats, and in the tropics, are most common in montane environments. While typically described as a wind-pollinated genus, recent evidence suggests that some species may be partially insect pollinated.
Juncus species often prefer wetland habitats, such as salt marshes and seeps. For this reason, they often interact with water-borne pollutants and are therefore suspected to uptake these pollutants when they are present in the environment. Research suggests strategic planting of Juncus species may be an effective tactic to clean contaminated water through biotic methods.
Juncus species are important members of the ecosystems they inhabit, providing food and creating habitat for many other organisms, including microbes, insects, amphibians, fish, and birds. Certain species have also been shown to alter the often heavily waterlogged soils they grow in around their roots, increasing the oxygen concentration and changing the pH. Beyond this, Juncus species across their range have been used in diverse ecological studies, including those relating to precipitation effects on marsh species, salt tolerance in brackish wetland plants, the effects of Juncus presence on plant diversity, and the effects of wetland plants on microbial soil communities.
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
Uses Species of genus Juncus are used by cultures around the world for various purposes. The fibrous stems lend themselves to making cordage, and cultures including indigenous peoples of California, South Africa, the Karabakh region, and pre-industrial Scandinavia have used this material to make baskets and candle wicks. There are also potential medical uses for Juncus, with both traditional medicinal uses from China and indigenous Americans as well as findings in modern medical science.
Classification
The genus Juncus was first named by Carl Linnaeus in his 1753 . The type species of the genus was designated by Frederick Vernon Coville, who in 1913 chose the first species in Linnaeus' account, Juncus acutus. Juncus can be divided into two major groups, one group with cymose inflorescences that include bracteoles, and one with racemose inflorescences with no bracteoles.
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. Plants of the World Online accepts Juncinella but treats the others as synonyms of Juncus.
The genus is divided into the following subgenera and sections: Juncus subg. Juncus sect. Juncus sect. Graminei sect. Caespitosi sect. Stygiopsis sect. Ozophyllum sect. Iridifolii Juncus subg. Poiophylli sect. Tenageia sect. Steirochloa sect. Juncotypus sect. Forskalina
Species
As of July 2025, Plants of the World Online accepts 342 species:
Juncus acuminatus Juncus acutiflorus Juncus acutiusculus Juncus acutus Juncus aemulans Juncus alatus Juncus alexandri Juncus allioides Juncus alpigenus Juncus × alpiniformis Juncus alpinoarticulatus Juncus amabilis Juncus amplifolius Juncus amplus Juncus amuricus Juncus anatolicus Juncus anceps Juncus andersonii Juncus andinus Juncus antarcticus Juncus anthelatus Juncus arcticus Juncus aridicola Juncus articulatus Juncus astreptus Juncus atratus Juncus australis Juncus austrobrasiliensis Juncus baekdusanensis Juncus balticus Juncus bassianus Juncus batrachium Juncus benghalensis Juncus beringensis Juncus biflorus Juncus biglumis Juncus biglumoides Juncus bolanderi Juncus brachycarpus Juncus brachycephalus Juncus brachyphyllus Juncus brachyspathus Juncus brachystigma Juncus brasiliensis Juncus brevibracteus Juncus brevicaudatus Juncus breviculmis Juncus breweri Juncus × brueggeri Juncus bryoides Juncus bryophilus Juncus bufonius Juncus bulbosus Juncus burkartii Juncus caesariensis Juncus caespiticius Juncus canadensis Juncus capensis Juncus capillaceus Juncus capillaris Juncus castaneus Juncus cephalostigma Juncus chiapasensis Juncus chlorocephalus Juncus chrysocarpus Juncus clarkei Juncus compressus Juncus concinnus Juncus concolor Juncus confusus Juncus conglomeratus Juncus continuus Juncus cooperi Juncus cordobensis Juncus coriaceus Juncus × correctus Juncus covillei Juncus crassistylus Juncus crispus Juncus curtisiae Juncus curvatus Juncus cyperoides Juncus debilis Juncus decipiens Juncus × degenianus Juncus densiflorus Juncus deosaicus Juncus diastrophanthus Juncus dichotomus Juncus diemii Juncus diffusissimus Juncus × diffusus Juncus digitatus Juncus distegus Juncus dolichanthus Juncus dongchuanensis Juncus × donyanae Juncus dregeanus Juncus drummondii Juncus dubius Juncus dudleyi Juncus dulongjiongensis Juncus durus Juncus duthiei Juncus ebracteatus Juncus echinocephalus Juncus ecuadoriensis Juncus edgariae Juncus effusus Juncus elbrusicus Juncus elliottii Juncus elongatus Juncus emmanuelis Juncus engleri Juncus ensifolius Juncus equisetinus Juncus ernesti-barrosi Juncus exiguus Juncus exsertus Juncus falcatus Juncus × fallax Juncus fascinatus Juncus fastigiatus Juncus fauriei Juncus fauriensis Juncus fernandez-carvajaliae Juncus filicaulis Juncus filiformis Juncus filipendulus Juncus fimbristyloides Juncus firmus Juncus flavidus Juncus fockei Juncus foliosus Juncus fominii Juncus fontanesii Juncus fugongensis Juncus × fulvescens Juncus ganeshii Juncus georgianus Juncus gerardi Juncus giganteus Juncus glaucoturgidus Juncus gonggae Juncus × gracilescens Juncus gracilicaulis Juncus gracillimus Juncus grandiflorus Juncus greenei Juncus gregiflorus Juncus grisebachii Juncus guadeloupensis Juncus gubanovii Juncus gymnocarpus Juncus haenkei Juncus hallii Juncus harae Juncus heldreichianus Juncus hemiendytus Juncus heptopotamicus Juncus hesperius Juncus heterophyllus Juncus himalensis Juncus holoschoenus Juncus homalocaulis Juncus hondurensis Juncus hookeridis Juncus howellii Juncus hybridus Juncus hydrophilus Juncus imbricatus Juncus inflexus Juncus ingens Juncus interior Juncus × inundatus Juncus jacquinii Juncus jaxarticus Juncus jinpingensis Juncus kelloggii Juncus khasiensis Juncus kingii Juncus kleinii Juncus krameri Juncus kraussii Juncus kuohii Juncus laccatus Juncus laeviusculus Juncus lancangensis Juncus × lancastriensis Juncus × langii Juncus leiospermus Juncus × lemieuxii Juncus leptospermus Juncus lesueurii Juncus leucanthus Juncus leucomelas Juncus liebmannii Juncus littoralis Juncus llanquihuensis Juncus lomatophyllus Juncus longiflorus Juncus longii Juncus longirostris Juncus longistamineus Juncus longistylis Juncus luciensis Juncus luzuliformis Juncus macrandrus Juncus macrantherus Juncus macrophyllus Juncus magellanicus Juncus marginatus Juncus maritimus Juncus maroccanus Juncus maximowiczii Juncus megacephalus Juncus megalophyllus Juncus meianthus Juncus membranaceus Juncus mertensianus Juncus micranthus Juncus microcephalus Juncus milashanensis Juncus militaris Juncus minimus Juncus minutulus Juncus modicus Juncus mogadorensis Juncus mollis Juncus × montellii Juncus × montserratensis Juncus × murbeckii Juncus mustangensis Juncus × neglectus Juncus nepalicus Juncus nevadensis Juncus nodatus Juncus × nodosiformis Juncus nodosus Juncus novae-zelandiae Juncus nupela Juncus oblongus Juncus × obotritorum Juncus obtusiusculus Juncus occidentalis Juncus ochraceus Juncus ochrocoleus Juncus orchonicus Juncus × oronensis Juncus orthophyllus Juncus oxycarpus Juncus oxymeris Juncus pallescens Juncus pallidus Juncus paludosus Juncus papillosus Juncus parryi Juncus patens Juncus pauciflorus Juncus pelocarpus Juncus perpusillus Juncus persicus Juncus pervetus Juncus petrophilus Juncus phaeanthus Juncus phaeocephalus Juncus planifolius Juncus polyanthemus Juncus polycephalos Juncus potaninii Juncus prismatocarpus Juncus procerus Juncus prominens Juncus przewalskii Juncus psammophilus Juncus punctorius Juncus pusillus Juncus pygmaeus Juncus pylaei Juncus radula Juncus ramboi Juncus ranarius Juncus ratkowskyanus Juncus rechingeri Juncus rectus Juncus regelii Juncus remotiflorus Juncus repens Juncus requienii Juncus revolutus Juncus rigidus Juncus riparius Juncus roemerianus Juncus rohtangensis Juncus × ruhmeri Juncus × sallandiae Juncus salsuginosus Juncus sandwithii Juncus sarophorus Juncus saximontanus Juncus scheuchzerioides Juncus scirpoides Juncus scrobilatus Juncus secundus Juncus semisolidus Juncus setchuensis Juncus sherei Juncus sikkimensis Juncus snowii Juncus socotranus Juncus sonderianus Juncus soranthus Juncus sorrentinoi Juncus sparganiifolius Juncus spectabilis Juncus sphacelatus Juncus sphaerocarpus Juncus spumosus Juncus squarrosus Juncus stipulatus Juncus striatus Juncus × stuckeyi Juncus stygius Juncus × subatratus Juncus subcaudatus Juncus subglaucus Juncus subnodulosus Juncus subsecundus Juncus subtilis Juncus subulatus Juncus subulitepalus Juncus supiniformis Juncus taonanensis Juncus tenageia Juncus tenuis Juncus texanus Juncus textilis Juncus thomasii Juncus thompsonianus Juncus thomsonii Juncus tiehmii Juncus tingitanus Juncus tobdeniorum Juncus torreyi Juncus trachyphyllus Juncus trichophyllus Juncus triformis Juncus triglumis Juncus trigonocarpus Juncus trilocularis Juncus turkestanicus Juncus uncialis Juncus uniflorus Juncus uruguensis Juncus usitatus Juncus vaginatus Juncus × valbrayi Juncus validus Juncus valvatus Juncus vaseyi Juncus venturianus Juncus virens Juncus wallichianus Juncus xiphioides Juncus yui
Formerly placed here Juncinella capitata (as Juncus capitatus ) Juncinella cephalotes (as Juncus cephalotes ) Juncinella obliqua (as Juncus obliquus ) Juncinella picta (as Juncus pictus ) Juncinella rupestris (as Juncus rupestris ) Juncinella scabriuscula (as Juncus scabriusculus ) Juncinella stenopetala (as Juncus stenopetalus )
References