Species: Collema tenax sens lat
Photos: On wall and concrete post. Bantry, Cork, SW Ireland.
Dark greenish-black thallus, very swollen when wet. The crowded jelly-like lobes are often hidden by the abundant reddish-brown apothecia. Isidia usually absent. Frequent and very variable.
C. tenax var. ceranoides, rarely fertile, narrow ascending lobes,
C. tenax var. vulgare usually very fertile with plumper lobes than C. tenax var. tenax.
Collema tenax var. corallinum is rarely recorded, +/- crustose, the apothecia disc surrounded by coralloid crown.
Common on mortar in walls, basic soils, sand and clay.
Chemical reactions negative.