Hydrocotyle phoenix

Fire pennywort
Closeup photo of flowers and leaves. The scale bar is 5mm.

Priority Two — Poorly Known Taxa (DEC)
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Apiales
Family: Araliaceae
Genus: Hydrocotyle
Species:
H. phoenix
Binomial name
Hydrocotyle phoenix
A.J.Perkins

Hydrocotyle phoenix is a species of annual pennywort and is commonly called fire pennywort. It is only known to grow in south-west Australia, specifically in fire prone habitats; it is unique in this regard as it is the only species of Hydrocotyle known to have a fire adapted life-history.[1] The specific epithet "phoenix" references this fire adapted life history as in Greek mythology, a phoenix experiences rebirth by rising from ashes, much like how this plant rises from the ashes after a wildfire.

Description

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A. Habitat B. Umbel of flowers C. Fruiting umbel D. Typical leaf E. Habitat of fertile plants

Hydrocotyle phoenix is a low growing annual herb which grows 4–15 centimeters (1.6–5.9 in) tall and up to 100 centimeters (39 in) wide with a sprawling habit. The leaves grow from a basal rosette. The leaves are palmately lobed and 5-20 mm long by 7-26 mm wide and covered in small hairs. The flowers are borne in a compact umbel with about 10-20 flowers. The flowers themselves are small, only 4-6 mm wide, and white. The flowers have only 5 white petals and lack a calyx. The fruits are schizocarps about 1 mm in size.[1]

Atypically for this group of plants, H. phoenix is a fire-ephemeral plant, meaning that it forms a soil seed bank in the soil and its germination is triggered by wildfire.[1] It will typically not grow unless prompted by a wildfire. Like many plants from Australia, its life cycle requires fire.

Hydrocotyle phoenix was discovered in 2015. It is most morphologically most similar to Hydrocotyle hispidula, Hydrocotyle blepharocarpa, and Hydrocotyle geraniifolia.[1] Its evolutionary position within Hydrocotyle has not yet been determined.

Range

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Hydrocotyle phoenix is only known from Karri Forest within D'Entrecasteaux National Park in Western Australia. The plant is locally abundant, but due to having a very small range, it is currently listed as Priority 2[2] as not enough data exists to ascribe it a conservation code.

References

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  1. ^ a b c d Perkins, Andrew J. (2017). "Rising from the ashes - Hydrocotyle phoenix (Araliaceae), a new annual species from south-western Australia". Telopea. 20: 41–47. doi:10.7751/telopea11313. Retrieved 29 November 2020.
  2. ^ Western Australian Herbarium, Biodiversity and Conservation Science. "FloraBase—the Western Australian Flora". florabase.dpaw.wa.gov.au. Retrieved 29 November 2020.