Usnea fragilescens var. mollis (All Fungi)
Thallus 3-5(-8) cm tall, mostly subpendant to erect, flaccid, main branches 1.5-2 mm diam., originating over the whole of the thallus length with relatively few, thinner, side branches which often arise at ± right angles from these main branches. Primary branches much elongate, distinct, thick, fusiform (often divided into long, somewhat inflated segments), often constricted and annulate where they join the main stem, giving a characteristic overall combed appearance. Fibrils few or absent, axils at an angle of 60-90°. Thallus surface very pale grey to green, often ± pellucid when wet, brown to jet-black for 1-2 mm above the ± attenuated base, shiny (resembling broken glass), smooth. Papillae usually numerous, evenly and densely distributed, low, broader than high, often inconspicuous. Soralia even, ± flat to slightly concave with a distinct rim, large, conspicuous, rounded, discrete, widely spaced. Isidiomorphs irregularly present, mostly absent on mature soralia. Medulla lax.
Anamorph: not known.
Teleomorph: not known.
Chemistry: thallus C–, K+ yellow-red, KC–, Pd+ red (usnic, stictic, menegazziaic and ± cryptostictic, ± norstictic and ± constictic acids).
Considered to be of Least Concern (Woods & Coppins 2012).
This is a semi-pendulous species with a blackened base. Often very pale green when fresh, it has a distinctly pellucid appearance, especially when moist. The surface of the main branches, which together have a distinct combed appearance, is minutely marbled and appears glassily uneven (x20). The main branches are gradually tapered towards their point of attachment where they are often cracked. The medulla is very lax and the cortex easily yields to pressure. Isidia are numerous on young branchlets and when these are abraded they are more or less replaced by rounded soralia in older parts.
Usnea fragilescens var. mollis differs from var. fragilescens in the following characters: it is subdichotomously and more richly branched, especially towards the base, the stalk-like holdfast is not attenuated towards the base, the primary branches are shorter and not fusiform, and the soralia are often densely isidiate.
In GB&I, recorded from W British Isles, most frequent in W Scotland.
On broad-leaved trees in moist sheltered woodland by rivers and Salix carr, rarely on rocks.