Class
Subclass
Family
Genus
Classification
Nomenclature
Scientific Name:
Equisetum fluviatile L., Sp. Pl. 1062 (1753)
Synonymy:
Lectotype (selected by Hauke 1978): Herb. Linn. No 1241.6, LINN.
Etymology:
Vernacular Name(s):
water horsetail
Description
Aerial stems monomorphic. Stems erect, 400–600 mm high, 2.5–5 mm in diameter, green, sparsely branched with undivided lateral branches arising in whorls; stem ridges nearly smooth; grooves 12–16; central hollow c. 4/5 the diameter of the stem; leaf sheaths pale brown or green with black teeth, 5–8 mm long. Strobili terminal on green stems, 6–10 mm long, 4–5 mm in diameter, apices obtuse.
Recognition
Equisetum fluviatile is recognised by its monomorphic and sparsely branched stems, black-tippped leaf sheaths with 12-16 grooves, and its obtuse strobilus. It is the rarest species of Equisetum in New Zealand.
Distribution
North Island: Auckland.
Altitudinal range: c. 40 m.
A widespread northern temperate species (Hauke 1978); known only from one collection near Huntly.
Habitat
Muddy pools on a stream margin. Plants occupied an area of 2 m² resulting from a deliberate planting in a nearby fishpond, but the colony was subsequently eradicated.
Biostatus
Exotic
First Record
de Lange (1988) – as Equisetum palustre; Webb et al. (1995). Voucher: AK 185311, 1988.
Notes
A cultivated population of this plant has been recorded from Eskdale, Napier where it was deliberately planted by the owner of the land who sold aquatic plants for ornamental purposes (de Lange 1988). In New Zealand E. fluviatile is an Unwanted Organism.
Bibliography
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.
de Lange, P.J. 1988: A new Equisetum species adventive in New Zealand. Auckland Botanical Society Journal 43: 68–72.
Hauke, R.L. 1978: A taxonomic monograph of Equisetum subgenus Equisetum. Nova Hedwigia 30: 385–455.
Linnaeus, C. 1753: Species Plantarum. Impensis Laurentii Salvii, Stockholm.
Webb, C.J.; Sykes, W.R.; Garnock-Jones, P.J.; Brownsey, P.J. 1995: Checklist of dicotyledons, gymnosperms, and pteridophytes naturalised or casual in New Zealand: additional records 1988–1993. New Zealand Journal of Botany 33: 151–182.
