Panicum effusum, known as hairy panic grass, is a perennial grass native to Australia and New Guinea.It is widespread and abundant throughout Australia, occurring most commonly in less fertile sandy or clay soils, but also in pastures, woodlands, and disturbed areas.It is highly tolerant of drought conditions, and especially enjoys full sun.
A tufted, warm season grass, hairy panic is short lived, germinating in spring and flowering in summer and fall.It grows in tufts to 0.7m (21 inches) tall.The leaf blades are dusty green in color, and hairy on the edges.Flowers grow as a highly branched inflorescence (panicle), in which the branches are angled out to make a fluffy flowerhead rather than growing in a tighter, compact form.When the seeds mature, the dried panicle breaks off and as blown by the wind, dispersing the seeds. Seeds also have been described as dispersing by sticking to mud on cars.
Hairy panic is a high quality and palatable food source for grazing stock up until flowering.It is best suited for light grazing, but can sustain heavier grazing and regenerates well if it is allowed to rest from grazing pressure during flowering and reseeding.After rainfall, this species responds with effusive growth.
In February of 2016, broken off portions of the hairy panic grass blew into the town of Wangratta, in Victoria Australia in huge quantities over the course of many days. While periodic large outbreaks are not uncommon throughout Australia, the year’s very dry conditions following drought-breaking rains were credited as inducing its excessive growth, probably in a nearby untended field.These tumbleweeds accumulated in piles higher than six feet, in some areas, causing a messy nuisance to residents.
Grazing livestock, notably sheep, that eat new growth of P. effusum (i.e. soon after rainfall) in large quantities or as a large percentage of their diet can suffer from a syndrome called yellow-bighead. This is a fatal condition, especially in young animals, caused by toxins called saponins that accumulate in the leaves.These toxins are uv reactive and cause heightened sensitivity of the animals skin cells to sunlight.In the absence of shade, the animals succumb to skin damage, inflammation, and subsequent liver damage and jaundice.
Stubble quail (Coturnix pectoralis), yellowhammer (Emberiza citrinella) and red-browed finches (Emblema temporalis) are recorded to eat the seeds.
(Benson and McDougall 2005; Bern 2016; Boatman et al. 2003; Darcey 1990; McNally 1956; New South Wales department of primary industries 2007; Quinn 2014; Ramzy 2016; Read 1994)
Panicum effusum, commonly known as hairy panic, is a grass native to inland Australia.[2] It occurs in every mainland state,[3] as well as New Guinea. In dry conditions, the fast-growing grass can become a tumbleweed.
Hairy panic is a perennial grass that reaches 70 centimetres (28 in) high.[3] The leaves have tubercle-based hairs and are up to 5–30 centimetres (2.0–11.8 in) long by 0.4–1 centimetre (0.16–0.39 in) wide. The seed spikes are typically 5–50 centimetres (2.0–19.7 in) long, with the spikelets 2–3 millimetres (0.079–0.118 in) long.[2]
Prolific Scottish botanist Robert Brown described Panicum effusum in his 1810 work Prodromus Florae Novae Hollandiae et Insulae Van Diemen.[4] It still bears its original name. Ferdinand von Mueller described Panicum convallium, which he recorded from the banks of the Torrens and Gawler Rivers, on the Murray River and along the Flinders Ranges, in 1855.[5]
Common names include branched panic, hairy panic, effuse panic, native millet and poison panic.[6]
Found across Australia, particularly in the east and Papua New Guinea,[1] hairy panic occurs on low- to medium-nutrient clay soils over shale or conglomerate.[7] Its large range, abundance and stable population mean that hairy panic is classified as Least Concern on the IUCN Red List, and in fact may be becoming more abundant.[1]
“Hairy panic” is found on the following ecoregions in Australia: Shrubland, grass downs, tropical savanna, desert, woodlands, lowland rainforest, tropical rainforests, montane grasslands, sub-alpine grassland, mangroves, xeric scrub and temperate rainforests.
Panicum effusum produces a dry, single-seeded, indehiscent fruit which is eaten by the stubble quail.[7] The seeds are wind-borne, though can also be transported in mud on cars.[7]
The flowering of this plant occurs during summer. It is highly drought-tolerant, but is sensitive to frost.
Under extremely dry conditions, the fast-growing grass becomes a tumbleweed (that has evolved to disperse seeds) and can become a nuisance in residential areas due to the accumulation of grass stalks.[8] In February 2016, the town of Wangaratta, Victoria, was invaded by large numbers of tumbleweeds of the plant, which piled up to roof height in places.[8] Some residents blamed the problem on a local farmer who had failed to upkeep his paddock.[8]
Hairy panic uses C4 carbon fixation,[9] giving it an advantage in conditions of drought and high temperature.[10]
Hairy panic is a component of pastures, though not usually abundant. It is of moderate nutritional value to livestock.[9] Sheep consuming large quantities of hairy panic within 2–6 weeks of rain can suffer from photosensitivity and the fatal disease “yellow-bighead”.[6][8]
It also has some bush food value. The seeds can be ground and baked. Although there are plenty of seeds they may not be easy to collect.[11]
A large area of Panicum effusum Panicum effusum, commonly known as hairy panic, is a grass native to inland Australia. It occurs in every mainland state, as well as New Guinea. In dry conditions, the fast-growing grass can become a tumbleweed.
