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Name

Eriachne armittii

F.Muell. ex Benth.

Longawn Wanderrie grass
Annual Wanderrie grass

This species is very widespread north of the Tropic of Capricorn in the Northern Territory and Queensland. It is a spreading to ascending annual, 14-50 cm high, becoming reddish with age. Leaves and stems have a covering of short or long hairs with warty base. Leaves are cauline (arising along the stem) with blades to 14 cm long (Fig. 1). Inflorescences or flowering branches terminate the stem and appear well exserted some distance from or partially enclosed in leaf axils. The inflorescences or flowering branches are contracted panicles with branches arising along a central stem, panicles 2.5-7 cm long, 0.8-1.8 cm wide. Eriachne armittii has spikelets (the basic flowering unit) consisting of two glumes encompassing two bisexual florets (modified flowers) (Fig. 2). The florets are shorter than the glumes, with the lemma of each floret giving rise to a curved awn 15-45 mm long, the palea of each floret is split into two small awns 1-6 mm long.

 

Botanical Description

An annual species 14-50 cm high, becoming reddish. The culms or stems are hispid or villous with tubercle-based hairs or partly glabrous. Leaves hispid or villous with tubercle-based hairs; leaf blade to 14 cm long and up to 6 mm wide. The inflorescences are contracted panicles, 2.5-7 cm long, 0.8-1.8 cm wide. Spikelets are defined by two glumes 7-11 (-12.5) mm long, each with a short awn or bristle to 3 mm long. The glumes encompass two bisexual florets which are much shorter than the glumes (2.5-4 mm long). The lemma of each floret is awned, the lemma awn is 15-45 mm long, with the palea of each floret splitting to form two awns much shorter than the lemma awn, 1-6 mm long (Fig. 2). The lemma is densely hairy with silky hairs exceeding the apex by up to 4 mm, grooves are absent but two depressions are present near the lemma apex.

 

Diagnostic Features

Eriachne armittii is one of many species of Eriachne characterised by long awned spikelets, the awns curled, curved or bent. Other long awned species of Eriachne which occur in the region and may be easily confused with this species are E. burkittii, E. glauca, E. squarrosa, E. stipacea, E. vesiculosa and E. rara. Some of these species are more easily distinguished than others. Most are treated in this guide, however some of the key differences between the species are shown in Table 1. In other regions of Australia e.g. the Northern Territory, additional species may also need to be considered. Eriachne armittii is distinguished by the combination of the following characters, an annual habit, the absence of bladder like sacs on the upper leaf surface, a contracted inflorescence, the glume usually hairy, the florets being distinctly shorter than the glumes and the bifid two awned palea. Users are encouraged to consult Lazarides (2005) or Simon & Alfonso (2011) for more detail on distinguishing between these species.

Characters useful in diagnosing 7 long awned Eriachne species found in the Quinkan region of CYP

Natural Values

This species is likely to provide seed for granivorous or seed eating animals.

Habitat

Widespread north of the Tropic of Capricorn in the Northern Territory and Queensland and collected from a few localities west of the Northern Territory border in Western Australia. Recorded growing on a variety of substrates including seasonally wet sites, sometimes saline or disturbed ground (Lazarides 2005, Simon 2011).

Land Management Notes

Species of this genus are considered generally to be of low forage value (Lazarides 2002).

 

 

Fig. 1. Herbarium sheet of Eriachne armittii (CNS136196).
Fig. 1. Herbarium sheet of Eriachne armittii (CNS136196).

 

Fig. 2. Mature spikelet of E. armittii (MBA6969) (scale bar = 1 cm).
Fig. 2. Mature spikelet of E. armittii (MBA6969) (scale bar = 1 cm).

 

 

 

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].