The species was described in 2009 by Toby Spribille and Christian Printzen during inland-rainforest surveys of British Columbia. The holotype specimen, collected from a soft standing snag on the west bank of the Incomappleux River, Selkirk Mountains (700 m a.s.l.), is housed in the Canadian Museum of Nature herbarium, with isotypes (duplicates) in Bergen and Frankfurt collections. The epithet combines Latin lignum ('wood') and mollis ("soft"), reflecting the species' strict preference for punky, decaying timber.[2]
Although the ascus structure resembles that of Micarea, sequence data from the nuclear internal transcribed spacer (ITS) and mitochondrial SSU regions place the lichen firmly within Biatora. The chemistry and especially the prolific pycnidia separate it from superficially similar taxa: it differs from B.rufidula in having many more apothecia (fruiting bodies) and narrower, 0–1-septate spores, and from the European "Catillaria" alba in its longer conidia and lobaric acid chemistry. An earlier, unpublished name (Lecidea carnea Spribille 2006) is a later homonym and therefore invalid.[2]
Description
Biatora ligni-mollis develops a thin, crust-forming thallus that is mostly immersed in, or barely lifts above, the surface of decaying conifer wood. Where the thallus is visible it appears white to pale cream and breaks into tiny cracked or granular areoles , together covering patches up to about 13 × 2.5cm. Each surface granule is corticate, with the cortex only 10–25μm thick, and encloses a layer of short-celled fungal filaments that weave around the green, rounded photobiont cells (3.5–13μm across). The crust produces no soredia or isidia, and no hypothallus is evident. Under long-wave ultraviolet light the thallus glows brilliant white—a reaction caused by lobaric acid, a compound rarely recorded in Biatora—while standard spot-tests are otherwise negative.[2]
Reproductive structures are conspicuous. Reddish-brown apothecia may reach densities of 170 per square centimetre, each 0.3–0.9mm across with a usually undulating, persistent margin and a flat to strongly convex disc . The gelatinised proper exciple —35–75μm thick—contains masses of colourless crystals that dissolve in potassium hydroxide solution. Within a 105–215μm-tall hymenium, Micarea-type asci hold eight narrowly ellipsoid ascospores that are 7–11 × 1.8–2.8μm and remain simple or at most one-septate at maturity. Flask-shaped pycnidia, 0.07–0.12mm wide, are abundant and generate colourless, ellipsoid to rod-shaped conidia measuring about 4.2 × 1.0μm.[2]
Habitat and distribution
All verified collections come from the humid inland temperate rainforest belt of south-eastern and central British Columbia. The lichen grows exclusively on the soft, punky wood of long-dead western redcedar (Thuja plicata) or western hemlock (Tsuga heterophylla) snags within ancient cedar–hemlock stands where the canopy has remained closed for many centuries. Micro-sites are shaded, constantly moist, and usually between 650 and 820m (2,130 and 2,690ft) elevation.[2]
As of its original publication, the species had been confirmed from two valleys: the upper Incomappleux River (Selkirk Mountains) and the Penfold Valley near Quesnel Lake, each harbouring small, old-growth remnants that are now targeted for logging. Its apparent dependence on decadent conifer snags in late-successional forest suggests that B.ligni-mollis could be highly vulnerable to ongoing timber extraction.[2]
1 2 3 4 5 6 7 Spribille, Toby; Björk, Curtis R.; Ekman, Stefan; Elix, John A.; Goward, Trevor; Printzen, Christian; Tønsberg, Tor; Wheeler, Tim (2009). "Contributions to an epiphytic lichen flora of northwest North America: I. Eight new species from British Columbia inland rain forests". The Bryologist. 112 (1): 109–137. doi:10.1639/0007-2745-112.1.109.
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