THE LICHEN FLORA OF THE BASILDON AREA 149
Fraxinus stumps, Thrift Wood, Bicknacre (1972, IMH); trunks of Ulmus,
Stock (1973, IMH); Fraxinus trunk, Dunton Lodge, Herongate (1974,
PME-B); Ulmus stump, disused barracks, Langdon Hills (1974, PME-B);
Salix stump and bole of Fraxinus, Westley Heights, Langdon Hills (1974
PME-B); old Ulmus stump by St Mary's Church, Runwell (1974, PME-B).
L. muralis (Schreb.) Rabenh.
Very common on asbestos-cement, concrete and mortar; rare on sand-
stone. 51/68, 69, 78, 79.
A conspicuous species on asbestos-cement sheet and tiled roofs and
concrete tiled roofs throughout the area. Abundant on the roofs of the
houses of Basildon New Town. It occurs only rarely on sandstone grave-
stones (1971-74; IMH, PME-B, SJH).
L. polytropa (Hoffm.) Rabenh.
Scarce on sandstone. 51/69.
Horizontal surfaces of chest-tomb, All Saints' Church, Hutton (1974,
PME-B); horizontal surface of gravestone level with the ground, Con-
gregational Church, Billericay (1974, PME-B).
Lecidea granulosa (Hoffm.) Ach.
Frequent on rotting stumps, logs, palings and decaying vegetation.
51/68, 69,79,52/70.
In damp places throughout the area.
L. lucida (Ach.) Ach.
Frequent on brick walls; also on sandstone and mortar. 51/69, 79, 52/70.
A conspicuous species, often covering large areas on the vertical surfaces
of brick walls, and on the mortar between the bricks. Also frequently
found on the vertical surfaces of churchyard headstones, especially in the
crevices of the engravings (1971-74; IMH, PME-B, SJH).
L. quernea (Dicks.) Ach.
Rare on Fraxinus. 15/69.
Fraxinus bole overhanging ditch, Norsey Farm, Billericay (1973,
PME-B).
L. uliginosa (Schrad.) Ach.
Scarce (or overlooked) on rotting wood. 51/69, 52/70.
Decaying Quercus root, Thrift Wood, Bicknacre (1972, IMH); rotting
stumps, Dunton Lodge, Herongate (1974, PME-B).
Lecidella scabra (Tayl.) Hertel & Leuckert
Scarce and sterile on sandstone, limestone and mortar/sandstone niches.
51/69.
On horizontal sandstone gravestone level with the ground, Congre-
gational Church. Billericay (1974, PME-B); in the niches between mortar
and sandstone of a chest-tomb, and on limestone walls of All Saints'
Church, Hutton (1974, PME-B).