Schistophoron, Stirt.

Torres, Jean Marc, Spielmann, Adriano Afonso, Aptroot, André, Cardoso, Karen Fernandes & Honda, Neli Kika, 2020, The lichen genus Schistophoron Stirt. (Ascomycetes, Graphidaceae) in Brazil with a world key to the species, Cryptogamie, Mycologie 20 (13), pp. 211-217 : 216

KEY TO THE SPECIES OF SCHISTOPHORON

1. Ascospores muriform, ≥15.0 Μm long; psoromic acid present ................. S. muriforme Weerakoon & Aptroot

— Ascospores transversely septate or submuriform, ≤15.0 Μm long; psoromic acid absent ............................... 2

2. Ascospores transversely septate; lichexanthone present or secondary substances absent ................................ 3

— Ascospores transversely septate to submuriform; stictic and norstictic acid present ...................................... 4

3. Ascospores transversally 1-septate; lichexanthone present; ascomata orange pruinose; prothallus orange-brown ...................................................................................................... S. aurantiacum Aptroot & Sipman

— Ascospores transversally 2-3 septate; secondary substances absent; ascomata epruinose; prothallus brown ........ ........................................................................................................................................... S. variabile Tibell

4. Ascomata constricted at the base, 0.4-0.9 mm long, 0.3-0.6 mm high; ascospores 11-15 × 6-8 Μm, submuriform (2-3 transverse and 1 longitudinal septa) ................................................................................... S. tenue Stirt.

— Ascomata not constricted at the base, 0.5-2.0 mm long, 0.25-0.4 mm high; ascospores submuriform (1 transverse and 1 longitudinal septum), (6-)7-9(-10) × 6-8 Μm ..................... S. indicum Kr.P.Singh & Swarnalatha