Juncus

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Juncus
Juncus.conglomeratus.2.jpg
Habitus of J. conglomeratus
Juncus.squarrosus3.-.lindsey.jpg
Flower of J. squarrosus
Scientific classification
Kingdom:
Plantae
(unranked):
Angiosperms
(unranked):
Monocots
(unranked):
Commelinids
Order:
Poales
Family:
Juncaceae
Genus:
Juncus
Type species
Juncus acutus
Synonyms[1]
  • Cephaloxys Desv., illegitimate superfluous name
  • Tristemon Raf. 1838, illegitimate homonym, not Raf. 1819 (Juncaginaceae) nor Klotzsch 1838 (syn of Erica in Ericaceae) nor Scheele 1848 (syn of Cucurbita in Cucurbitaceae)
  • Juncastrum Fourr., not validly published
  • Juncinella Fourr., not validly published
  • Phylloschoenus Fourr., not validly published
  • Tenageia (Dumort.) Fourr.
  • Microschoenus C.B.Clarke

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Juncus is a genus of monocotyledonous flowering plants, commonly known as rushes. It is the largest genus in the family Juncaceae, containing around 300 species.[2]

Description

Rushes of the genus Juncus are herbaceous plants that superficially resemble grasses or sedges.[3] They have historically received little attention from botanists; in his 1819 monograph, James Ebenezer Bicheno described the genus as "obscure and uninviting".[4]

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.[3] The stems are round in cross-section, unlike those of sedges,[3] which are typically somewhat triangular in cross-section.[5]

In Juncus section Juncotypus (formerly called Juncus subg. Genuini),[6] 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.[7]

Distribution and ecology

Juncus has a cosmopolitan distribution, with species found throughout the world, with the exception of Antarctica.[2] They typically grow in cold or wet habitats, and in the tropics, are most common in montane environments.[3]

Classification

In Juncus effusus (and other species in J. sect. Juncotypus), the bract appears as a continuation of the stem, and the inflorescence appears lateral.

The genus Juncus was first named under the rules of the International Code of Nomenclature for algae, fungi, and plants by Carl Linnaeus in his 1753 Species Plantarum. The type species of the genus was designated by Frederick Vernon Coville in 1913; he chose the first species in Linnaeus' account, which was Juncus acutus.[6] Juncus can be divided into two major groups, one group with cymose inflorescences that include bracteoles, and one with racemose inflorescences with no bracteoles.[6]

The genus is divided into the following subgenera and sections:[6]

  • Juncus subg. Juncus
  1. sect. Juncus
  2. sect. Graminei (Engelm.) Engelm.
  3. sect. Caespitosi Cout.
  4. sect. Stygiopsis Kuntze
  5. sect. Ozophyllum Dumort.
  6. sect. Iridifolii Snogerup & Kirschner
  • Juncus subg. Poiophylli Buchenau
  1. sect. Tenageia Dumort.
  2. sect. Steirochloa Griseb.
  3. sect. Juncotypus Dumort.
  4. sect. Forskalina Kuntze

Species

Selected Juncus species
J. inflexus
J. jacquinii
J. monanthos
J. squarrosus
J. trifidus

The Plant List accepts the following species in the genus Juncus:[8]

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References

  1. ↑ Kew World Checklist of Selected Plant Families
  2. ↑ 2.0 2.1 Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ 3.0 3.1 3.2 3.3 Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  6. ↑ 6.0 6.1 6.2 6.3 Lua error in package.lua at line 80: module 'strict' not found.
  7. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ Lua error in package.lua at line 80: module 'strict' not found.

External links

  • Media related to Lua error in package.lua at line 80: module 'strict' not found. at Wikimedia Commons
  • Data related to Juncus at Wikispecies
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