Family Restionaceae
Synonyms: Centrolepidaceae APNI*
Description: Perennial herbs with a rush- or sedge-like habit; tufted or with creeping rhizomes often partly covered by scales; or (subfamily Centrolepidoideae) diminutive tufted annuals. Stems (culms) green, terete to angular or flattened, simple or branched, straight or flexuous, solid or hollow.
Leaves in adult plants reduced to sheaths, often with a small linear or subulate lamina; sheaths closely imbricate or loose, margins overlapping, at least at the base, or (Centrolepidoideae) leaves not reduced to sheaths.
Flowers in spikelets, usually with imbricate rigid glumes, some of the outer ones usually empty; in several genera the spikelet structure not apparent because of clustering of spikelets; spikelets 1–many-flowered, either similar or very different in the 2 sexes, solitary and terminal, or axillary, or arranged in a racemose inflorescence. Male and female inflorescences either similar or very different. Flowers usually actinomorphic, 3- or 2-merous, bisexual or more usually unisexual and plants dioecious, in some species bisexual or monoecious, small, each in the axil of a ± scarious glume; bracts on pedicel 1 or 2 or absent. Perianth in 2 whorls, rarely absent; tepals 3–6, glume-like or scarious, erect. Male: stamens 2 or 3, opposite the inner tepals; filaments free and filiform; anthers 1-locular, dorsifixed, exserted or not-exerted, dehiscing by longitudinal slits; pistillode often present. Female: staminodes 2, 3, or absent; ovary superior, sessile or shortly stipitate, 1–3-locular according to the number of carpels fully developed or (Centrolepidoideae) carpels numerous on an extended axis; styles or style branches1–3; ovule solitary in each loculus, pendulous.
Fruit a loculicidal capsule, 2- or 3-angled or 1-locular, or a small nut.
Distribution and occurrence: World: 40 genera, 585 species, all except 1 species Southern Hemisphere, with main centres of diversity in southern Africa & SW Australia, also in E Australia, New Zealand, New Guinea, Malesia, Chile & Falkland Is. Australia: 24 genera, c. 160 species, all States. Restionaceae characteristically occur on sandy or peaty soils low in nutrients, often in seasonally wet sites.
External links:
Angiosperm Phylogeny Website (Family: Restionaceae, Order: Poales)
Wikipedia Restionaceae characteristically occur on sandy or peaty soils low in nutrients, often in seasonally wet sites. The classification of Australian Restionaceae depends largely on phylogenetic studies (Briggs et al., Taxon 63: 24–46 (2014), also see Restionaceae in online Flora of Australia. The species formerly known in Australia as Restio are not closely allied to the true Restio species of South Africa.
Centrolepis and Aphelia were formerly placed in family Centrolepidaceae but, following analyses of DNA data, this family is now included in Restionaceae as subfamily Centrolepidoideae. The diminutive plants of this subfamily in many ways resemble seedlings of other Restionaceae. The inflorescence of Centrolepidoideae was formerly interpreted as a pseudanthium, including a number of male and female flowers each consisting of a single stamen or carpel, but this has been reinterpreted and is seen as a bisexual flower in a spikelet structure. The carpel number is increased from that in other Restionaceae with the carpels borne separately on an elongated axis.
Text by A. L. Quirico & B. G. Briggs, updates B.G. Briggs, Aug. 2022
Taxon concept:
| | Key to the genera | |
| 1 | Diminutive tufted annuals; leaves not reduced to sheaths | 2 |
| Perennial plants, tufted or rhizomatous; leaves reduced to sheaths on the culms (stems) | 3 |
| 2 | Inflorescence a spike with 6–11 distichous bracts | Aphelia |
| Inflorescence a head enclosed by a pair of bracts
Back to 1 | Centrolepis |
| 3 | Ovary 2- or 3-locular; anthers exserted; styles or style branches 2 or 3; fruit a capsule | 4 |
| Ovary and fruit 1-locular; anthers exserted or not exserted; styles or style branches 1 or 3; fruit a small nut
Back to 1 | 8 |
| 4 | Culms compressed; stamens 2; style branches 2; capsule 2-locular | Eurychorda |
| Culms terete or almost terete; stamens 2 or 3; styles or style branches 2 or 3; capsule 2- or 3-locular
Back to 3 | 5 |
| 5 | Stamens, style branches and capsule loculi 2; spikelet structure clearly apparent | 6 |
| Stamens, style branches and capsule loculi 3; spikelet structure often obscured by clustering of spikelets
Back to 4 | 7 |
| 6 | Male and female flowers attached to the subtending glume by a very short axis and falling with the glume; seed surface mostly smooth | Baloskion |
| Male and female flowers not attached to the subtending glume and not falling with the glume; seed surface with longitudinal lines of convex cells
Back to 5 | Chordifex |
| 7 | Culm central cavity round; culm stomates scattered | Lepyrodia |
| Culm central cavity 2- or 3 - angular; stomates arranged in horizontal bands so that the culm surface is mottled with fine pale bands
Back to 5 | Sporadanthus |
| 8 | Plants monoecious; male spikelet terminal, solitary; female spikelets solitary in the axils near the base of the culm; style 1, undivided | Coleocarya |
| Plants dioecious; style branches3
Back to 3 | 9 |
| 9 | Female spikelets axillary, 1-flowered with several sterile glumes; upper leaf sheaths green, with a spreading or reflexed subulate tip; anthers exserted | Empodisma |
| Female spikelets terminal on culms or culm branches; leaf sheaths not as above; anthers not exserted
Back to 8 | 10 |
| 10 | Female spikelets several-flowered; culms mostly unbranched below the inflorescence, straight; fruit a nut with a parenchymatous or membranous pericarp; male spikelets 3–5 mm long | Leptocarpus |
| Female spikelets 1-flowered; culms mostly much-branched, often flexuous; fruit a nut with a woody pericarp; male spikelets 5–8 mm long
Back to 9 | Hypolaena |
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