Thallus crustaceous non-corticate. Spores simple. Spores small, thin-walled. Spores colourless 1. Lecidea Ach. Spores brown 2. *Orphniospora Koerb. Spores large, thick-walled 3. Mycoblastus Norm. Spores 1-septate. Spores small, thin-walled 4. Catillaria Th. Fr. Spores large, thick-walled 5. Megalospora Mey. and Flot. Spores elongate, 3-multi-septate. Spores elongate, narrow, thin-walled 6. Bacidia A. Zahlbr. Spores elongate, large and thick-walled 7. Bombyliospora De Not. Spores muriform. Spores colourless; on trees 8. Lopadium Koerb. Spores colourless to brown; on rocks 9. Rhizocarpon Th. Kr. Thallus warted or squamulose, corticate. Spores elongate, 1-7-septate, thin-walled 10. Toninia Th. Fr. Thallus of upright podetia-like small fronds. Spores ellipsoid, becoming 1-septate 11. *Sphaerophoropsis Wain. XXXII. _PHYLLOPSORACEAE_ A small family of exotic lichens with a somewhat more developed thallus than that of the Lecideaceae, being in both of the genera squamulose or almost foliose. The apothecia are without a thalline margin; they are biatorine or lecideine; the hypothecium is formed of plectenchyma and is purple-red in one species, _Phyllopsora furfuracca_. The two genera differ only in spore characters. There are fifteen species, mostly corticolous, belonging to _Phyllopsora_; only one, from New Zealand, is recorded for _Psorella_. Spores simple 1. *Phyllopsora Müll.-Arg. Spores elongate, septate 2. *Psorella Müll.-Arg. XXXIII. _CLADONIACEAE_ Associated with Lecideaceae in the type of apothecium, but differing widely in thallus formation. The latter is of a twofold type: the primary thallus is crustaceous, squamulose, or very rarely foliose; the secondary thallus or podetium, upright, simple or branched, is terminated by the apothecia, or broadens upwards to cup-like scyphi. Algal cells, Protococcaceae, according to Chodat, _Cystococcus_. Much attention has been given to the origin and development of the podetia in this family. They are superficial on granule or squamule except in the monotypic Himalayan genus _Gymnoderma_ where they are marginal on the large leaf-like lobes. Though in origin the podetia are doubtless fruit stalks, they have become in most cases vegetative in function. The fruits are coloured yellowish, brown or red (or dark and carbonaceous in _Pilophorus_), and are borne on the tips of the branches or on the margins of the scyphi. In _Glossodium_ and _Thysanothecium_—the former from New Granada, the latter from Australia—the apothecia occupy one side of the widened surface at the tips.