Skip to main content

Service Notice

The Western Australian Herbarium’s collections management system, WAHerb, and DBCA’s flora taxonomic names application, WACensus, have been set to read-only mode since 1 October 2025. Recent taxonomic changes are not currently being reflected in Florabase, herbarium collections, or the census. Due to the rapidly approaching holiday season and associated agency and facility soft closures, along with the substantial work involved in data mapping, cleaning, and verification, the migration to the new collection management software is not expected to occur before 1 March 2026, when a further update will be provided. Please reach out to us if you have any questions or concerns.

The notice period started at 9:45 am on Friday, 12 December 2025 +08:00 and will end at 12:00 pm on Monday, 2 March 2026 +08:00.

Oligarrhena R.Br.

Reference
Prodr. 549 (1810)
Name Status
Current

Scientific Description

Family Epacridaceae.

Habit and leaf form. Shrubs; evergreen; leptocaul, or pachycaul. Helophytic to xerophytic. Leaves minute; alternate; spiral, or four-ranked; ‘herbaceous’, or leathery; imbricate; sessile; non-sheathing; simple. Leaf blades entire; flat; parallel-veined; cross-venulate, or without cross-venules. Leaves without stipules. Leaf blade margins flat. Stem anatomy. Nodes unilacunar. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous, or ornithophilous. Pollination mechanism unspecialized.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in spikes. Inflorescences compound (the numerous small spikes forming a leafy raceme); axillary. Flowers bracteate; bi- bracteolate; minute; fragrant, or odourless; laterally compressed; 4 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present; intrastaminal; of separate members (4 distinct scales). Perianth with distinct calyx and corolla; 8; 2 -whorled; isomerous. Calyx 4; 1 -whorled; polysepalous; imbricate; exceeded by the corolla; regular; persistent. Corolla 4; 1 -whorled; gamopetalous; lobed. Corolla lobes about the same length as the tube. Corolla valvate; campanulate; regular; glabrous abaxially; glabrous adaxially; white, or yellow; persistent, or deciduous. Androecium 2, or 4. Androecial members adnate (to the corolla); all equal; free of one another; 1 -whorled. Androecium exclusively of fertile stamens, or including staminodes. Staminodes when present, 2; representing the alternate deficient members. Stamens 2. Staminal insertion in the throat of the corolla tube. Stamens remaining included; reduced in number relative to the adjacent perianth; oppositisepalous; all alternating with the corolla members. Filaments glabrous; filiform (very short). Anthers basifixed, or adnate; becoming inverted during development, their morphological bases ostensibly apical in the mature stamens; non-versatile; dehiscing via longitudinal slits (by a single median slit); finally introrse (inverting during development); unilocular, or bilocular; bisporangiate; unappendaged. Pollen shed as single grains; without viscin strands. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary plurilocular; 2 locular. Gynoecium stylate. Styles 1; very short; attenuate from the ovary; apical. Stigmas 1; minute, truncate, or clavate, or capitate. Placentation axile. Ovules 1 per locule; pendulous; non-arillate; anatropous.

Fruit and seed features. Fruit fleshy, or non-fleshy; indehiscent; a drupe (small). The drupes with one stone. Fruit 1 seeded. Seeds endospermic. Endosperm oily. Seeds wingless. Embryo well differentiated. Cotyledons 2. Embryo straight. Seedling. Germination phanerocotylar.

Physiology, biochemistry. Aluminium accumulation not found. Photosynthetic pathway: C3.

Geography, cytology, number of species. Native of Australia. Endemic to Australia. Australian states and territories: Western Australia. South-West Botanical Province.

Additional characters Prophylls few. Corolla lobes erect.