# Orthoceras strictum

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Species of orchid

Bird's-mouth orchid In Ku-ring-gai Chase National Park, Australia Scientific classification Kingdom: Plantae Clade: Embryophytes Clade: Tracheophytes Clade: Spermatophytes Clade: Angiosperms Clade: Monocots Order: Asparagales Family: Orchidaceae Subfamily: Orchidoideae Tribe: Diurideae Genus: Orthoceras Species: O. strictum Binomial name Orthoceras strictum R.Br.[1] Synonyms[1] Orthoceras sp. aff. strictum

***Orthoceras strictum***, commonly known as the **bird's-mouth orchid**[2] or **horned orchid**,[3] is a species of [orchid](/source/Orchid) [native](/source/Indigenous_(ecology)) to eastern and southern [Australia](/source/Australia), [New Zealand](/source/New_Zealand) and [New Caledonia](/source/New_Caledonia). It has between two and five linear leaves and up to nine yellowish green, brownish or blackish flowers with two long, erect to spreading [lateral](https://en.wiktionary.org/wiki/lateral) [sepals](/source/Sepal).

Yellowish green form in [Cathedral Rock National Park](/source/Cathedral_Rock_National_Park)

## Description

*Orthoceras strictum* is a terrestrial, [perennial](/source/Perennial_plant), [deciduous](/source/Deciduous), [herb](/source/Herbaceous_plant) with an underground [tuber](/source/Tuber) and a tuft of between two and five linear to thread-like, grass-like leaves, 150–300 mm (6–10 in) long and 2–3 mm (0.08–0.1 in) wide. Up to nine flowers 8–10 mm (0.3–0.4 in) wide are borne on a rigid flowering stem 300–600 mm (10–20 in) tall. Flower colour varies from blackish, brownish, maroon to yellowish green. The dorsal sepal is egg-shaped and forms a hood over the rest of the flower, 9–12 mm (0.4–0.5 in) long and 8–10 mm (0.3–0.4 in) wide. The lateral sepals are linear, horn-like, 20–25 mm (0.8–1 in) long, about 1 mm (0.04 in) wide and erect, spreading or curved. The [petals](/source/Petal) are oblong, 8–10 mm (0.3–0.4 in) long, about 3 mm (0.1 in) wide and hidden inside the dorsal sepal. The [labellum](/source/Labellum_(botany)) is 6–10 mm (0.2–0.4 in) long and has three lobes. The middle lobe is elliptic to egg-shaped, 6–7 mm (0.2–0.3 in) long, 5–6 mm (0.20–0.24 in) wide and the side lobes are 5–6 mm (0.20–0.24 in) long, about 1.5 mm (0.06 in) wide. There is a pyramid-shaped [callus](/source/Labellum_(botany)) near the base of the labellum. Flowering occurs from November to February.[2][3][4]

## Taxonomy and naming

*Orthoceras strictum* was first formally described in 1810 by [Robert Brown](/source/Robert_Brown_(botanist%2C_born_1773)) and the description was published in his book *[Prodromus Florae Novae Hollandiae et Insulae Van Diemen](/source/Prodromus_Florae_Novae_Hollandiae_et_Insulae_Van_Diemen)*.[5][6] The [generic](/source/Genus) name (*Orthoceras*) is derived from the [Ancient Greek](/source/Ancient_Greek) words *orthos* meaning "straight"[7]: 578 and *keras, keratos* meaning "horn,[7]: 422 which alludes to the upright lateral sepals.[8] The [specific epithet](/source/Botanical_nomenclature) (*strictum*) is a [Latin](/source/Latin) word meaning "straight" or "tight".[7]: 760

## Distribution and habitat

The bird's-mouth orchid is widespread but uncommon and occurs in [New South Wales](/source/New_South_Wales), [Queensland](/source/Queensland), [South Australia](/source/South_Australia), [Tasmania](/source/Tasmania), [Victoria](/source/Victoria_(Australia)) and New Caledonia. It grows in a wide range of habitats from grassy forest to heath. The differences between this species and *[Orthoceras novae-zeelandiae](/source/Orthoceras_novae-zeelandiae)* from New Zealand are "very slight and dubious".[9]

## Conservation

*Orthoceras strictum* is listed in Tasmania as "rare" under the Tasmanian Government *[Threatened Species Protection Act 1995](/source/Threatened_Species_Protection_Act_1995)*.[10]

## References

1. ^ [***a***](#cite_ref-APC_1-0) [***b***](#cite_ref-APC_1-1) ["*Orthoceras strictum*"](https://biodiversity.org.au/nsl/services/apc-format/display/56871). Australian Plant Census. Retrieved 20 October 2025.

1. ^ [***a***](#cite_ref-RBGS_2-0) [***b***](#cite_ref-RBGS_2-1) Bernhardt, Peter. ["*Orthoceras strictum*"](http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Orthoceras~strictum). Royal Botanic Garden Sydney. Retrieved 17 March 2018.

1. ^ [***a***](#cite_ref-RBGV_3-0) [***b***](#cite_ref-RBGV_3-1) Ohlsen, Daniel. ["*Orthoceras strictum*"](https://vicflora.rbg.vic.gov.au/flora/taxon/6464c337-dcff-40c7-ae8a-aaf6ef259587). Royal Botanic Gardens Victoria. Retrieved 17 March 2018.

1. **[^](#cite_ref-Jones_4-0)** Jones, David L. (2006). *A complete guide to native orchids of Australia including the island territories*. Frenchs Forest, N.S.W.: New Holland. p. 283. [ISBN](/source/ISBN_(identifier)) [1877069124](https://en.wikipedia.org/wiki/Special:BookSources/1877069124).

1. **[^](#cite_ref-APNI_5-0)** ["*Orthoceras strictum*"](https://id.biodiversity.org.au/instance/apni/459721). APNI. Retrieved 17 March 2018.

1. **[^](#cite_ref-R.Br._6-0)** Brown, Robert (1810). [*Prodromus Florae Novae Hollandiae et Insulae Van Diemen*](https://www.biodiversitylibrary.org/item/21771#page/186/mode/1up). London. pp. 317–318. Retrieved 17 March 2018.

1. ^ [***a***](#cite_ref-RWB_7-0) [***b***](#cite_ref-RWB_7-1) [***c***](#cite_ref-RWB_7-2) Brown, Roland Wilbur (1956). *The Composition of Scientific Words*. Washington, D.C.: Smithsonian Institution Press.

1. **[^](#cite_ref-8)** Les Robinson - Field Guide to the Native Plants of Sydney, [ISBN](/source/ISBN_(identifier)) [978-0-7318-1211-0](https://en.wikipedia.org/wiki/Special:BookSources/978-0-7318-1211-0) page 251

1. **[^](#cite_ref-NZPCN_9-0)** ["*Orthoceras novae-zeelandiae*"](http://www.nzpcn.org.nz/flora_details.aspx?ID=1070). New Zealand Plant Conservation Network. Retrieved 17 March 2018.

1. **[^](#cite_ref-dpipwe_10-0)** ["*Orthoceras strictum* - horned orchid"](https://www.naturalvaluesatlas.tas.gov.au/downloadattachment?id=14223). Tasmanian Government Department of Primary Industries, Parks, Water and Environment. Retrieved 17 March 2018.

## External links

- Media related to [Orthoceras strictum](https://commons.wikimedia.org/wiki/Orthoceras_strictum) at Wikimedia Commons

Taxon identifiers Orthoceras strictum Wikidata: Q3014832 Wikispecies: Orthoceras strictum APNI: 56871 BOLD: 431604 CoL: 6SWTF eFloraSA: Orthoceras_strictum EoL: 1136225 GBIF: 5324063 iNaturalist: 55664 IPNI: 649495-1 NCBI: 78819 NZOR: 7db71c2c-064f-49ea-866d-f7b01696e89c Open Tree of Life: 753616 Plant List: kew-144221 POWO: urn:lsid:ipni.org:names:649495-1 Species+: 61523 Tropicos: 50022747 VicFlora: 6464c337-dcff-40c7-ae8a-aaf6ef259587 WFO: wfo-0000261037

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Adapted from the Wikipedia article [Orthoceras strictum](https://en.wikipedia.org/wiki/Orthoceras_strictum) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Orthoceras_strictum?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.