Pimelea spicata, commonly known as Spiked Rice-flower or Pink Spiked Rice-flower, is a species of flowering plant in the family Thymelaeaceae. It is a small, slender shrub endemic to New South Wales, Australia. The species is notable for its distinctive terminal flower spikes and its critically endangered conservation status.
Description Pimelea spicata typically grows as an erect or decumbent shrub, reaching heights of 10 to 40 centimetres. Its stems are slender and often hairy. The leaves are opposite, narrow-elliptic to linear, usually 5–20 mm long and 1–4 mm wide, and are dark green with a paler underside. The most distinguishing feature of Pimelea spicata are its flowers, which are arranged in dense, elongated, terminal spikes. Each spike can contain numerous small, tubular flowers, which are typically pink, though occasionally white. The flowers are bisexual and occur in the axils of small, overlapping bracts. Flowering mainly occurs in spring and early summer, typically from September to December.
Taxonomy and Naming Pimelea spicata was first formally described in 1827 by Robert Brown in his work Proteaceas Novas, or Supplementum primum prodromi florae Novae Hollandiae. The specific epithet "spicata" is derived from the Latin word spicatus, meaning "spiked," referring to the arrangement of its flowers in spikes. The genus name Pimelea comes from the Greek word pimele, meaning "fat or lard," possibly referring to the oily seeds of some species within the genus.
Distribution and Habitat This species is endemic to the Cumberland Plain in western Sydney, New South Wales, Australia. It predominantly occurs in remnant patches of Cumberland Plain Woodland and related grassy woodlands, which are characterised by shale-derived soils. Historically, it was more widespread, but its habitat has been significantly reduced due to urban development and agricultural expansion.
Conservation Status Pimelea spicata is listed as Critically Endangered under the New South Wales Biodiversity Conservation Act 2016 and as Endangered under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The primary threats to its survival include:
- Habitat loss and fragmentation: Ongoing urban development, road construction, and agriculture continue to destroy and divide its remaining habitat.
- Weed invasion: Competition from exotic species, particularly aggressive grasses and herbs, outcompetes Pimelea spicata for resources.
- Inappropriate fire regimes: Both too frequent and infrequent fires can negatively impact the species' life cycle and seed germination.
- Grazing: Browsing by both native and introduced herbivores can damage plants and reduce reproductive success.
- Poor recruitment: Limited seed dispersal, low germination rates, and environmental stressors hinder the establishment of new plants.
Conservation efforts focus on protecting existing populations, managing threats within reserves, habitat restoration, and ex-situ conservation through seed banking and propagation.