Juncus acuminatus
Common name
sharp-fruited rush
Family
Juncaceae
Flora category
Vascular – Exotic
Structural class
Rushes & Allied Plants
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
Conservation status
Not applicable
Brief 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 to 10 light brown flowers/capsules (fruit).
Distribution
Common throughout the North Island and northern South Island, usually lowland.
Habitat
Margins of flowing and still water bodies, drains and wet pasture.
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).
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely in uplands (non-wetlands).
Features
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.
Flowering
Spring to early summer
Flower colours
Brown
Fruiting
Summer to autumn
Life cycle
Seed dispersed by animals, water or contaminated machinery.
Year naturalised
1915
Origin
North and South America
Reason for introduction
Unknown, seed or soil contaminant
Control techniques
Not controlled in New Zealand.
Etymology
juncus: From the Latin jungere ‘to tie or bind’, the stems of some species being used to make cord (Johnson and Smith)
Notes on taxonomy
Subgenus Juncus, Section Ozophyllum (Septati) Kirschner (2002: Juncaceae 2)
Attribution
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA). Features description from Healy and Edgar (1980).
References and further reading
Healy, A.J.; Edgar, E. (1980). Flora of New Zealand, Volume III. Adventive Cyperaceous, Petalous and Spathaceous Monocotyledons. Government Printer, Wellington. 220pp.
Johnson PN, Brooke PA (1989). Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington. 319pp.
Johnson, A. T. and Smith, H. A (1986). Plant Names Simplified: Their pronunciation, derivation and meaning. Landsman Bookshop Ltd: Buckenhill, UK.
Healy, A.J. (1982). Identification of weeds and clovers. New Zealand Weed and Pest Control Society Publication. Editorial Services Limited, Featherston. 299pp.
Kirschner, J. (compiler) (2002). Juncaceae 2: Juncus subg. Juncus, Species Plantarum: Flora of the World Part 7: 1-336.