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Classification
Class
Subclass
Family
Genus
Nomenclature
Scientific Name:
Equisetum hyemale L., Sp. Pl. 1062 (1753)
Synonymy:
Type: not designated (see Jarvis 2007)
Etymology:
Vernacular Name(s):
Dutch rush; rough horsetail; scouring rush
Description
Aerial stems monomorphic. Stems erect, 1000–2000 mm high, 5–15 mm in diameter, green, unbranched or with very occasional undivided lateral branches arising in whorls; stem ridges with two rows of tubercles; grooves 22–45; central hollow c. ⅔ the diameter of the stem; leaf sheaths pale green or white with black teeth and sometimes a second black band near the base of the sheath, 11–22 mm long. Strobili terminal on green stems, 8–16 mm long, 4–8 mm in diameter, apices apiculate.
Recognition
Equisetum hyemale is recognised by its monomorphic stems, its usually unbranched stems, black-tipped leaf sheaths with 22–45 grooves, and its apiculate strobilus. It is the tallest species in New Zealand.
Distribution
North Island: Northland, Auckland, Taranaki, Southern North Island.
South Island: Canterbury, Southland.
Altitudinal range: 5–40 m.
A widespread northern temperate species now known from localities at Whangārei Heads, Auckland City, New Plymouth, Levin, Christchurch, Otatara and Invercargill. Most of these records are of plants in gardens (sometimes derelict) where they are well established or spreading, and for which there is no direct evidence of deliberate cultivation. Only the populations in Taranaki and Levin are clearly adventive. The species has also been reported from Motueka, Greymouth, and Fox River (Clayson Howell pers. comm.) but without supporting herbarium specimens.
Habitat
In most of the known localities Equisetum hyemale appears to have been an escape from cultivation, or to have been occupying bare sections or derelict gardens. Many of the populations have now been eradicated. However, at the Levin site, plants have escaped from a rural property and occupy a large patch at the side of SH1.
Biostatus
Exotic
First Record
Healy (1994). Voucher: CHR 402611, 1993.
Notes
Equisetum hyemale in the northern hemisphere has been documented by Hauke (1963). In New Zealand, it is an Unwanted Organism.
Images
Bibliography
Biosecurity New Zealand 4 Aug 2011: Unwanted Organisms Register. http://www.biosecurity.govt.nz/pests/registers/uor
Brownsey, P.J.; Perrie, L.R. 2015: Equisetaceae. In: Breitwieser, I; Heenan, P.B.; Wilton, A.D. (ed.) Flora of New Zealand — Ferns and Lycophytes. Fascicle 6. Manaaki Whenua Press, Lincoln.
Hauke, R.L. 1963: A taxonomic monograph of the genus Equisetum subgenus Hippochaete. Nova Hedwigia Beiheft 8: 1–123.
Healy, A.J. 1994: A new Equisetum in New Zealand. New Zealand Botanical Society Newsletter 35: 7–8.
Jarvis, C.E. 2007: Order out of chaos: Linnaean plant names and their types. Linnean Society of London in association with the Natural History Museum.
Linnaeus, C. 1753: Species Plantarum. Impensis Laurentii Salvii, Stockholm.
