Juncus

Location & distribution maps

Phylogeny & links to associated information:

Internal links:             Angiosperms > Monocots > Commelinids  > Commelinids > Poales > Juncaceae > Juncus

External links:     Angiosperms > Monocots > Commelinids >

Wikipedia links:       Angiosperms > Monocots >   Commelinids  > Poales > Juncaceae > Juncus

Other links:     

Plant  information

Common name:                Rushes 

Conservation status:  unknown

Etymology:   

• x

Flowers:                  

• 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)

  • a stigma with three lobes

Fruit:                         

• x

Leaves:         

• x

Stem & branches: 

• The stems are round in cross-section

• Unlike those of sedges, which are typically somewhat triangular in cross-section

Roots:         

• x

Habit:        

• Herbaceous plants that superficially resemble grasses or sedges

• In Juncus section Juncotypus, which contains some of the most widespread and familiar species

  • the leaves are reduced to sheaths around the base of the stem 

  • the bract subtending the inflorescence closely resembles a continuation of the stem, giving the appearance that the inflorescence is lateral

Habitat:   

• They typically grow in cold or wet habitats, and in the tropics, are most common in montane environments

Distribution:                  

• Juncus has a cosmopolitan distribution, with species found throughout the world, with the exception of Antarctica

Species:                     

• World:           ~ 300 species

• Australia:      S,    G

• It is the largest genus in the family Juncaceae

Additional notes:     

• They have historically received little attention from botanists; in his 1819 monograph, James Ebenezer Bicheno described the genus as "obscure and uninviting"

• 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

• 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 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

  • Juncus can be divided into two major groups, one group with cymose inflorescences that include bracteoles, and one with racemose inflorescences with no bracteoles

  • The genus is divided into the following subgenera and sections:

    • Juncus subg. Juncus

    • sect. Juncus

    • sect. Graminei (Engelm.) Engelm.

    • sect. Caespitosi Cout.

    • sect. Stygiopsis Kuntze

    • sect. Ozophyllum Dumort.

    • sect. Iridifolii Snogerup & Kirschner

    • Juncus subg. Poiophylli Buchenau

    • sect. Tenageia Dumort.

    • sect. Steirochloa Griseb.

    • sect. Juncotypus Dumort.

    • sect. Forskalina Kuntze