Leptogium azureum sensu Galloway
Lichen azureus Sw. in Ach., Lich. suec. Prod.: 137 (1798).
Thallus submonophyllous to polyphyllous, dark blue-grey to distinctly bluish when dry, dark olive-greenish or leaden when wet, 2-10 cm diam., attached to substrate by scattered tufts of hairs, loosely adnate, corticolous, rarely saxicolous. Lobes rather papery, orbicular to elongate, apices rounded, 1-5 mm broad, margins entire to sublobulate. Upper surface smooth to somewhat roughened, never wrinkled-plicate, without isidia. Lower surface concolorous with upper surface, not tomentose. Apothecia common, often abundant, scattered, sessile to short pedicellate, laminal, 0.2-2.5 mm diam., disc concave to plane or subconvex, pale brown to dark red-brown, matt, proper exciple rarely seen, thalline exciple entire or with occasional, small, microphylline outgrowths, concolorous with thallus or pale white or buff. Ascospores ellipsoid to subfusiform, apices pointed, submuriform, 3-6 transverse septa and 1-2 longitudinal septa, 14-26 × 6-9 µm.
N: Northland to Wellington. S: Nelson to Fiordland. St: A: Widespread in shaded habitats on the bark of shrubs and trees, and on twigs of divaricating shrubs, in moderate shade in humid habitats. Often among moss.
Pantropical
L. azureum is distinguished from L. cyanescens by its lack of isidia and from most other species in New Zealand by the blue colour of the lobes. In early reports of New Zealand lichens it was referred to as L. tremelloides but this name is a synonym of L. azureum, see Jørgensen [ Norske Vidensk.-Akad. I. Mat. Naturvitensk. Kl. Skr. N.S. 36: 12-13 (1977)] and Jørgensen and James [ Lichenologist 15: 109-125 (1983)].
