Equisetum arvense
NPPA pest plant
Environmental Weed (2024)
Common names
horsetail
Biostatus
Exotic
Category
Vascular
Structural class
Ferns
Flower colours
No flowers
Detailed description
Erect, colony-forming, summer-green perennial, primitive fern-ally to 10-80 cm. All aerial parts die back in winter. Extensive, deep, freely branching rhizomes with round tubers. Stems of 2 types. Sterile stems green, 10-80 cm long, 1-5 mm diam, jointed, hollow, ribbed or grooved, very rough to touch (containing silica), with lateral branches in whorls; leaves are 10 mm green sheaths. Resembles pine seedling. Fertile stems pale brown, shorter, joints larger, unbranched, with pale brown 14 mm sheaths; producing terminal cones; appearing in early spring before sterile stems and dying quickly after shedding spores. Cones conspicuous, 4-40 mm long. Spores seldom produced in NZ.
Similar taxa
Equisetum hyemale rough horsetail is very similar but rare; has slender, taller, very rough, asparagus-like spears with black rings, no leaves, no (occ few small) branches, cones on green stems. E. fluviatile (rare).
Habitat
Terrestrial. Bare land, riversystems especially silty, sandy and gravely sites, streambanks.
Conservation status
Not applicable
Detailed taxonomy
Family
Ecology
Flowering
N/A
Year naturalised
1922
Origin
Arctic and temperate parts of the Northern Hemishpere.
Reason for introduction
Accidental.
Life cycle and dispersal
Perennial. Reproducing by spores instead of seeds, and by rhizomes, to which are attached small tubers. (Wax, Fawcett, Isley eds. 1981). Fruiting heads contain masses of tiny pale greenish spores in small pine-cone like structure. Stems tough and wiry, hollow, jointed, and of two types: fertile, producing fruiting heads and having large, easily separable joints, not branched; Sterile or vegetative, having much smaller joints, with lateral branches in whorls around the main stem. Leaves on sterile stems only, in the form of cup shaped toothed sheaths at the joints (Wax, Fawcett, Isley eds. 1981).
Plant is dispersed by river systems, soil movement, humans (popular with herbalists).
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]
FACU: Facultative Upland
Occasionally is a hydrophyte but usually occurs in uplands (non-wetlands).
Other information
Etymology
equisetum: From the Latin equus ‘horse’ and setum ‘bristle’, the barren growths resembling horses’ tails.
arvense: Growing in arable fields
National Pest Plant Accord species
This plant is listed in the 2020 National Pest Plant Accord. The National Pest Plant Accord (NPPA) is an agreement to prevent the sale and/or distribution of specified pest plants where either formal or casual horticultural trade is the most significant way of spreading the plant in New Zealand. For up to date information and an electronic copy of the 2020 Pest Plant Accord manual (including plant information and images) visit the MPI website.
Environmental Weed (2024)
This plant is named in a list of 386 environmental weeds in New Zealand 2024 prepared by DOC. 759 candidate species were considered for inclusion on this new comprehensive list of environmental weeds in New Zealand. The species considered were drawn from published lists of weed species, lists of plants that must be reported or managed by law if observed, existing national and regional programmes and agreements for pest management, and species already managed by the Department of Conservation (DOC). Candidate species were then assessed to see if they were fully naturalised and whether they have more than minor impacts in natural ecosystems. Read the full report here.
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.
EQUARV