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Dysphania pusilla
Conservation status
	; Nationally Endangered (NZ TCS)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Order:	Caryophyllales
Family:	Amaranthaceae
Genus:	Dysphania
Species:	D. pusilla
Binomial name
	Dysphania pusilla; Mosyakin & Clemants
Synonyms
	Chenopodium pusillum Hook.f.;

Dysphania pusilla, formerly Chenopodium pusillum, otherwise known as pygmy goosefoot or parahia in Māori, is a prostrate herb endemic to the north-eastern parts of South Island, New Zealand. Presumed extinct after 56 years without recorded observations, the species was rediscovered in 2015.

Description

Dysphania pusilla is an annual, puberulent herb, growing to around 20 centimetres (8 in) in length and often forming a cushion-like covering on surfaces such as clay and rocks. The herb is distinguishable from other species of the genus (such as the introduced Dysphania pumilio) through the slightly smaller seeds, a different number of tepals and the close positioning of the leaves in relation to each other. The herb, existing in both green and brown colour morphs,^[3] produces small green and yellow flowers during the warmer months.^[1]

Etymology

The name is derived from the term pusilla, which is the Latin word for 'very small'.^[4]

Location

Dysphania pusilla, a New Zealand endemic,^[1] is generally located in the north-eastern corner of the South Island of New Zealand;^[5] Harry Allan in his Flora of New Zealand [es] (1961) mentions that it does not grow south of 43°30'S.^[6]^[7] The plant is usually found in dry, sparsely-vegetated open spaces, including ephemeral wetlands, but has also been known to bloom in urban environments such as railway yards and agricultural land.^[8]

History

The plant was first recorded in 1864 as Chenopodium pusillum by Joseph Dalton Hooker in his systematic work Handbook of the New Zealand Flora. Missionary Richard Taylor in his book Te Ika a Maui: or, New Zealand and its inhabitants (1855) had recorded the Māori proverb

Tena te ringa tango parahia.

That is a hand which roots out the parahia.^[9]

—Māori proverb

—Richard Taylor's translation

explaining that "This saying is applied to a diligent husbandman. The parahia is a diminutive kind of spinach, which overruns their cultivations."^[10] Parahia was identified as Ctenopodium pusillum by botanist William Colenso in a paper presented to the Hawke's Bay Philosophical Institute on 9 June 1879.^[11] In 2008, botanists Sergei Leonidovich Mosyakin and Steven Earl Clemants re-allocated this taxon to the genus Dysphania.^[2]

The plant was prevalent until 1959, when the last known sample was located beside a railway siding in Christchurch, and although Colenso had described it as abundant in Maori cultivations,^[12] it got no mention in any lists of indigenous "weeds" affecting agriculture or horticulture,^[7] and was by 1999 considered data deficient.^[13] In 2012, "following repeated surveys in known or expected habitats at appropriate times", Dysphania pusilla was considered extinct.^[14]

Botanist Shannel Courtney, Department of Conservation's Technical Support Officer for Flora and Restoration and the 2008 Loder Cup recipient, stumbled upon a widespread growth of the species near a tributary of the Waiau Toa / Clarence River in January 2015, followed by reports of other specimens found in the Ruataniwha wetlands in the McKenzie Basin, and a third discovery in March in the Heron Basin in mid-Canterbury.^[15] Botanists speculate that seeds of D. pusilla lie dormant for decades awaiting suitable growing conditions.^[3] The plant is still threatened by habitat loss to date, due to introduced species and changes in land use for agricultural purposes and cattle grazing. Thus, in both 2017 and 2018, it was declared "Threatened - Nationally Endangered".^[1]

References

^ ^a ^b ^c ^d "Dysphania pusilla". New Zealand Plant Conservation Network. Retrieved 1 August 2020.
^ ^a ^b Sergei L. Mosyakin; Steven E. Clemants (2008). "Further Transfers of glandular-pubescent species from Chenopodium subg. Ambrosia to Dysphania (Chenopodiaceae)". Journal of the Botanical Research Institute of Texas. 1. Vol. 2. Botanical Research Institute of Texas. pp. 425–31. Retrieved 9 September 2016. Dysphania pusilla (Hook, f.) Mosyakin & Clemants, comb. nov. Basionym: Chenopodium pusillum Hook, f., Handh New Zealand Fl. 1:231. 1864.
^ ^a ^b "The re-discovery of the presumed extinct Dysphania pusilla" (PDF). Trilepidia. Wellington, New Zealand: New Zealand Plant Conservation Network. June 2015. Retrieved 9 September 2016.
^ "Latin definition for: pusillus, pusilla". Latin dictionary. Retrieved 19 September 2016.
^ "Rangers rediscover rare plants". Radio New Zealand. 7 April 2015. Retrieved 9 September 2016.
^ Harry Howard Allan; Lucy B. Moore; Elizabeth Edgar; Arthur John Healy (1961). Flora of New Zealand: Indigenous tracheophyta : monocotyledones except Gramineae. R.E. Owen, Govt. printer. p. 228. Retrieved 9 September 2016.
^ ^a ^b Leach, Helen (2005). "Gardens without weeds? Pre-European Maori gardens and inadvertent introductions". New Zealand Journal of Botany. 43 (1): 271–284. doi:10.1080/0028825x.2005.9512954.
^ W. R. Sykes; C. J. Webb; Phil J. Garnock-Jones (1988). Flora of New Zealand: Naturalised pteridophytes, gymnosperms, dicotyledons. Botany Division, D.S.I.R. ISBN 978-0-477-02529-4. Retrieved 9 September 2016.
^ Richard Taylor (1855). Te Ika a Maui: or, New Zealand and its inhabitants. Illustrating the origin, manners, customs, mythology, religion ... of the natives; together with the geology, natural history, productions, and climate of the country. Wertheim and Macintosh. p. 133. Retrieved 9 September 2016.
^ "ENZB – 1855 – Taylor, Richard. Te Ika a Maui — CHAPTER IX: WAKATAUKI, OR PROVERBS". University of Auckland (Early New Zealand Books). Retrieved 9 September 2016.
^ Colenso, William (1880). "Contributions towards a better knowledge of the Māori Race. Part II — Proverbs and proverbial sayings.". Transactions of the Royal Society of New Zealand. Vol. 12. Royal Society of New Zealand. pp. 108–47. Retrieved 9 September 2016. Tena te ringa tango parahia! Well-done the hand that roots up weeds! Applied to a steady worker in root-crop plantations. Parahia, a low-spreading weed (Ctenopodium pusillum), is particularly plentiful at Taupo.
^ Andersen, Johannes Carl (1926). "Popular names of New Zealand plants". Transactions and Proceedings of the Royal Society of New Zealand. Vol. 56. Royal Society of New Zealand. pp. 683–. Retrieved 9 September 2016.
^ Lange, P. J. de; Heenan, P. B.; Given, D. R.; Norton, D. A.; Ogle, C. C.; Johnson, P. N.; Cameron, E. K. (1999). "Threatened and uncommon plants of New Zealand" (PDF). New Zealand Journal of Botany. 37 (4): 603–628. doi:10.1080/0028825x.1999.9512657. hdl:10092/415.
^ Lange, PJ de; Galloway, DJ; Blanchon, DJ; Knight, A; Rolfe, JR; Crowcroft, GM; Hitchmough, R (2012). "Conservation status of New Zealand lichens". New Zealand Journal of Botany. 50 (3): 303–363. doi:10.1080/0028825x.2012.691426.
^ "'Extinct' native plants rediscovered". Department of Conservation (New Zealand). Retrieved 9 September 2016.