Xanthoparmelia semiviridis
≡Parmeliopsis semiviridis F. Muell ex Nyl., Syn. meth. lich. 2: 57 (1869).
≡Chondropsis semiviridis (F. Muell ex Nyl.) Cromb., Bot. J. Linn. Soc. 17: 397 (1879).
Descriptions : Flora (1985: 92 – as Chondropsis semiviridis). See also Elix (1994e: 35).
Chemistry : Cortex K−, UV−; medulla K+ pale brown, C−, Pd+ orange-red; containing usnic acid, fumarprotocetraric acid, succinprotocetraric acid and protocetraric acid (tr.).
S: E of the Main Divide. On soil (and freely windblown), in dry inland basins of Marborough (Molesworth), Canterbury (Balmoral, Mackenzie Country) and Central Otago, occasionally close to the coast in the suburbs of Christchurch (in grassland rough on Shirley golf course!), and very recently in alpine scree garden in the Dunedin Botanic Gardens, though the small population developed here has not survived the rapid growth of alpine plantings on the scree. It occurs on bare, arid soils in lowland (rarely), montane and subalpine grasslands heavily grazed by sheep and/or rabbits, and is often associated with Rumex acetosella and Thymus vulgaris in these depleted habitats. Also in arid and semi-arid deserts in microphytic soil crusts of SE Australia (Rogers 1971, 1977; Rogers & Lange 1972; Eldridge 1996; Eldridge & Tozer 1997; Eldridge & Koen 1998; Eldridge & Leys 1999; McCarthy 2003c, 2006).
Australasian
Illustrations : Martin & Child (1972: 113, pl. 25); Moore & Irwin (1978: 15, fig. 5); Filson & Rogers (1979: fig. 14A); Galloway (1981a: 528, fig. 1); Lumbsch & Kothe (1988: 326, fig. 1; 27, fig. 2); Flora of Australia 55 : xii, fig. 6 (1994); Eldridge & Tozer (1997: 39, fig. 4.19); Malcolm & Galloway (1997: 11, 118); Kärnefelt et al. (1998: 81, fig. 1K; 82, fig. 2C; 83, fig. 3B; 85, fig. 4A; 87, fig. 5A); Eldridge & Leys (1999: 158, fig. 1); Váczi & Hawksworth (2001: 514, fig. 1A) – all as Chondropsis semiviridis.
Xanthoparmelia semiviridis is characterised by: its vagant, unattached habit with no rhizines produced on the lower surface. When dry, it rolls up into a convex ball up to 30-mm diam. Within minutes of wetting it unrolls, changing into a dichotomously branched, foliose form. In its dry state, large numbers of X. semiviridis thalli often accumulate in windrows, along fences, alongside roadside gravel verges, and among small shrubs, grasses and other debris. In a recent study using a field-based wind tunnel Eldridge & Leys (1999) showed that continual bombardment of X. semiviridis thalli against both the soil surface and physical objects (fallen branches debris etc.) resulted in the breakdown of thalli into small, detached apical fragments that were easily moved by wind. They hypothesise that thallus fragments are likely to move with much higher frequencies than larger, intact thalli, and thereby provide a means of dispersal to new areas.
