Eriachne Triseta Nees Ex Steud
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Grasses of Cape Yorkork - Quinkan Country Eriachne triseta Nees ex Steud. This species is very widespread and common across northern Australia. It is an erect to sometimes drooping, tufted perennial between 60 cm and 120 cm high (Fig. 1). Plants are mostly glabrous with the base of the plant slightly thickened or knotty, and pubescent (softly hairy). Leaf blades are thin and bristle like to 25 cm long, with the flowering branch sparse and often drooping. Eriachne triseta has two bisexual florets (modified flowers) per spikelet (the basic flowering unit), each floret is distinctly, although shortly, three awned, a rare occurrence in the genus (Figs. 2a & b). Fig. 1. Habit of Eriachne triseta FACT SHEET: GRASSES OF CAPE YORK - QUINKAN COUNTRY - Eriachne triseta | PAGE 1 of 3 > BOTANICAL DESCRIPTION Spikelets are few per branch, each spikelet is defined A perennial species 60-120 cm high. The leaves and by two glumes 8-15 mm long, and contains two culms are mostly glabrous with the base of plant bisexual florets, the florets are shorter than the slightly thickened or knotty, pubescent. The leaf glumes. The lemma of each floret is awned, the lemma sheaths are usually half as long as the culm internode, awn is 8-14 mm long, with the palea of each floret and the blades are up to 25 cm long, are convolute, splitting to form two awns slightly shorter than the setaceous (bristle like), finely pointed and often lemma awn, between 6-11.5 mm long (Fig. 2a & b). flexuose (bent from side to side or curved). The Spikelets of this species are recorded as both inflorescence or flowering branches are open, often chasmogamous (pollinated when the flower is open) drooping panicles (with flowering branches arising and cleistogamous (self-pollinating with the flower along a central stem), 7-15 cm long, 2.5-4.5 cm wide. never opening) (Lazarides 1995). 1 cm 1 cm 1 cm Fig. 2a. Mature spikelet of E. triseta showing Fig. 2b. Mature spikelet of E. triseta showing base of Fig. 3. Mature spikelet of Aristida calycina showing three awns awned lemma and bifid palea awns arising from lemma and palea arising from lemma FACT SHEET: GRASSES OF CAPE YORK - QUINKAN COUNTRY - Eriachne triseta | PAGE 2 of 3 > DIAGNOSTIC FEATURES Eriachne triseta is easily distinguished by the three short awns arising from each floret, other species of Eriachne with paleas splitting into two awns have much longer lemma awns (> 15 mm) and more compact inflorescences. Superficially Eriachne triseta can be confused with species of Aristida, however close inspection of the florets (even with the naked eye) show that the awns of Aristida arise from the lemma in the floret (Fig. 3), while in E. triseta they are arise from both the lemma and the palea. > NATURAL VALUES This species is likely to provide seed for granivorous or seed eating animals and as a perennial offer habitat to fauna. > HABITAT Widespread in northern Australia and along the east coast of Queensland; also in Sri Lanka, India and throughout Southeast Asia. Often associated with sandy seasonally flooded habitats, coastal sand dunes, rocky slopes and plateaus associated with sandstone or laterite (Simon 2011). > LAND MANAGEMENT NOTES Species of this genus are considered generally to be of Fig 4. Map of CYP bioregion showing actual herbarium collections (from BRI and low forage value (Lazarides 2002). CNS) (solid circle) and site records (open circle) of Eriachne triseta. The green shading indicates areas where this species might also be found, based on similarity of habitat to locations where the species has been recorded. (Mapping supplied by P. Bannink, DES). Data attribution: Environment and Science, Queensland Government, Biodiversity status of pre-clearing and 2015 remnant regional ecosystems series - version 10.0 licensed under Creative Commons Attribution. RESOURCES: AVH (2017) Australia’s Virtual Herbarium, Council of Heads of Australasian Herbaria, <http://avh.chah.org.au>, accessed 30 May 2017. Lazarides, M. (1995) The genus Eriachne (Eriachneae, Poaceae). Australian Systematic Botany 8(3): 355-452. Lazarides, M. (2002) Economic attributes of Australian grasses. Flora of Australia 43: 213-245. Lazarides, M., Weiller, C.M. & McCusker, A. in Mallett, K. (ed.) (2005) Eriachne. Flora of Australia 44B: 132-175. Simon, B.K. & Alfonso, Y. (2011) AusGrass2, http://ausgrass2.myspecies.info/accessed on [20 March 2017]. For more information: www.capeyorknrm.com.au | 1300 132 262 This project is supported by the Queensland Government Department of Natural Resources and Mines through the Queensland Regional Natural Resource Management Investment Program FACT SHEET: GRASSES OF CAPE YORK - QUINKAN COUNTRY - Eriachne triseta | PAGE 3 of 3.