Angus's Onion Orchid  |  

Microtis angusii

Status: Endangered on the EPBC Act list

AngusÕs Onion Orchid is a terrestrial orchid, which grows to 25Ð60 cm tall. Leaves are 40Ð140
cm long and 4Ð8 mm wide, green, linear, hollow cylindrical and tapering in shape. Leaves are
usually much longer than flowering stems, which emerge from an aperture in the leaves,
approximately 12Ð20 cm above the soil. Flowering stems are 8Ð80 cm long and host 20Ð60 small
green flowers. Flowers are 2.5 mm in diameter, hood-shaped with a short point on the dorsal
sepal and a large labellum and lateral sepals. Petals are much smaller. The labellum has a glandlike callus on the apex, a single basal callus gland and a crisped edge to the labellum which is
tapered and lacks an apical notch. Fruits are 5Ð6 mm long and 3.5Ð4 mm wide, small, ellipsoidshaped and contain many small seeds. This description is drawn from Jones (1996) and OE (2019a).

Government evidence of impact of climate change:

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  • Australian Government, Conservation Advice, Microtis angusii

    The main factors that make the species eligible for listing in the Endangered category are small population size; very restricted distribution and population declines due to habitat loss; disturbance or modification; invasive species and climate change.

    Climate change Inappropriate fire Timing current Although flowering in Microtis species may be triggered regimes Confidence known by fire related cues (Bates 1986); some terrestrial orchids with shallow tubers may be killed by fires that Consequence major generate extreme soil heating (Duncan 2012).

    Catastrophic bushfires are increasingly likely to reoccur due to climate change.

    Additionally; increased temperature and changes to precipitation patterns may facilitate weed invasion; as weeds are expected to respond faster to climate change than native plants (Scott et al. 2014).

    Understand and ameliorate the effects of climate change on the species.

    In particular; grassy weeds can increase fuel Trend unknown load and alter fire regimes (Milberg Lamont 1995 Extent across the entire Setterfield et al. 2013).

    These altered fire regimes can range create conditions that are detrimental to the maintenance of native species and favourable to the establishment and spread of weeds (D’Antonio Vitousek 1992 Grigulis et al. 2005).

    The small population size and restricted distribution of Angus s Onion Orchid may increase the likelihood of extinction; following stochastic events; such as drought (OEH 2019a).