Callome multipartita
Thallus to 3-6 cm diam., foliose, rounded or irregular, deeply lobate and richly branched, loosely appressed to partly ascending, very fragile, not swollen when wet. Lobes 1-2 mm wide, often remaining partly separate, often fan-shaped, ± contorted, nodular and irregular, convex, often sub-cylindrical, repeatedly branched, usually not ascending. Upper surface ± dark olive-green to brown-black, matt, without isidia, often minutely longitudinally striate, ± swollen and semi-transparent when moist.
Anamorph: no information available.
Teleomorph: ascomata apothecia, common, scattered, laminal. Disc 1-2 mm diam., flat to convex with ± thick, entire, crenulate or lobulate thalline exciple. Ascospores 26-43 × 4.5-6.5 μm, ellipsoid-fusiform, sometimes curved, 3-septate.
Assessed as of Least Concern by Woods & Coppins (2012), but the species is listed as Nationally Scarce due to the small number of grid squares from which it is recorded.
Similar in some respects to Lathagrium, but readily distinguished from all other species of Collemataceae by the loosely attached, much-branched thallus with narrow, often partially discrete, notably convex-rounded, minutely striate lobes and the characteristic ellipsoidal-fusiform ascospores. When well-developed the thallus appears to be dendritically branched.
Trhoughout the western British Isles and over much of Ireland, but local in distribution.
On hard, sunny and exposed limestones, rarely on siliceous rock associated with shell-sand, often associated with Enchylium (Collema) polycarpon.