Juncus acuminatus
Common names
sharp-fruited rush
Biostatus
Exotic
Category
Vascular
Structural class
Rushes & Allied Plants
Simplified description
Upright leafy rush to 80 cm tall, leaves round with internal cross walls (feels like clicks if you hold base of leaf between finger and thumb and slide up), plant reddish with branched flower heads made up of many clusters of 6–10 light brown flowers/capsules (fruit).
Flower colours
Brown
Detailed description
Strictly erect tufted perennial, commonly reddish-tinged. Stems 30–80 cm high, distinctly septate internally just below inflorescence. Leaves terete or ± compressed with distinct transverse septa. Inflorescence very variable, 3–20 cm long, open, much-branched with 6–10-flowered clusters at ends of branches. Tepals 2.5–3.5 mm long, ± equal, narrow-lanceolate, stiff, acuminate. Stamens 3. Capsules 2.5–3.5 mm long, = or slightly > tepals, narrow, acute, shortly beaked, straw-coloured to brown.
Similar taxa
Similar to other tubular septate leaved rushes, but only J. acuminatus and J. canadensis have septate stems beneath the inflorescence. J. canadensis has tailed seeds, larger capsules, is more densely upright and lacks the reddish tinged appearance.
Distribution
Common throughout the North Island and northern South Island, usually lowland.
Habitat
Margins of flowing and still water bodies, drains and wet pasture.
Conservation status
Not applicable
Detailed taxonomy
Family
Synonyms
Verojuncus acuminatus (Michx.) Záveská Drábková & Proćków
Taxonomic notes
Subgenus Juncus, Section Ozophyllum (Septati) Kirschner (2002: Juncaceae 2)
Proćków et al. (2023) proposed a taxonomic segregation of Juncus into six genera based on molecular and morphological evidence. Whilst it has long been recognised that the current circumscription of Juncus includes morphologically divergent taxa—reflected in the recognition of numerous subgenera and sections—the consensus view of the NZPCN website taxonomy subcommittee, taking into consideration advice from Australian Juncus expert Dr Karen Wilson (NSW Herbarium) and others in Europe is that the generic segregations proposed need further consideration and testing. Accordingly, it has been decided to maintain the current broad circumscription of Juncus, but to include all new names as synonyms in factsheets. We thank, in particular, Dr Wilson for her helpful comments.
Ecology
Flowering
Spring to early summer
Fruiting
Summer to autumn
Year naturalised
1915
Origin
North and South America
Reason for introduction
Unknown, seed or soil contaminant
Control techniques
Not controlled in New Zealand.
Life cycle and dispersal
Seed dispersed by animals, water or contaminated machinery.
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely in uplands (non-wetlands).
Other information
Etymology
juncus: From the Latin jungere ‘to tie or bind’, the stems of some species being used to make cord (Johnson and Smith)
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
JUNACU
Referencing and citations
References and further reading
Healy, A. J. 1982. Identification of weeds and clovers. New Zealand Weed and Pest Control Society Publication. Editorial Services Limited, Featherston. 299 p.
Healy, A. J.; Edgar, E. 1980. Flora of New Zealand, Volume III. Adventive Cyperaceous, Petalous and Spathaceous Monocotyledons. Government Printer, Wellington. 220 p.
Johnson, P. N.; Brooke, P. A. 1989. Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington. 319 p.
Johnson, A. T.; Smith, H. A. 1986. Plant Names Simplified: Their pronunciation, derivation and meaning. Landsman Bookshop Ltd, Buckenhill, UK.
Kirschner, J. (compiler) (2002). Juncaceae 2: Juncus subg. Juncus, Species Plantarum: Flora of the World Part 7: 1–336.
Proćków, J., Záveská Drábková, L. 2023. A revision of the Juncaceae with delimitation of six new genera: nomenclatural changes in Juncus. Phytotaxa 622(1): 17–41.
Attribution
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA). Features description from Healy and Edgar (1980).
Some of this factsheet information is derived from Flora of New Zealand Online and is used under a Creative Commons Attribution 3.0 New Zealand licence.