Thallus crustaceous[1042]; spores simple, colourless 1. *Rhabdopsora Müll.-Arg. Thallus crustaceous; spores 1-septate, colourless 2. *Eolichen Zuk. Thallus crustaceous; spores muriform, brown 3. *Pyrenothrix Riddle[1043]. Thallus squamulose; spores numerous, simple 4. *Placothelium Müll.-Arg. Algal cells _Nostoc_. Thallus crustaceous; spores filiform, simple, colourless 5. *Hassea A. Zahlbr. Thallus fruticose; spores elongate, 3-septate, brown 6. Pyrenidium Nyl. Algal cells _Microcystis_ (_Polycoccus_). Thallus squamulose; fructification unknown 7. Coriscium Wainio. SERIES II. =GYMNOCARPEAE= SUBSERIES 1. =Coniocarpineae= This small subseries is marked by the peculiar “mazaedium” type of fruit with its disappearing asci. It forms a connecting link between the families with perithecia and those with apothecia. The thallus is crustaceous or fruticose, often poorly developed and sometimes absent. The algal cells are Protococcaceae or rarely _Trentepohlia_. XV. _CALICEACEAE_ The thallus is thinly crustaceous, sometimes brightly coloured, sometimes absent, taking no part in the formation of the fruits; these have upright stalks with a small capitulum, and often look like minute nails. One genus, _Sphinctrina_, is parasitic on the thallus of other lichens, mostly _Pertusariae_. Fruits with slender stalks. Spores simple. Spores colourless 1. Coniocybe Ach. Spores brown 2. Chaenotheca Th. Fr. Spores septate, brown. Spores 1-septate 3. Calicium De Not. Spores 3-7-septate 4. Stenocybe Nyl. Fruits with short thick stalks. Spores globose, brown (parasitic) 5. Sphinctrina Fries. Spores 1-septate, brown 6. *Pyrgidium Nyl. XVI. _CYPHELIACEAE_ Thallus crustaceous. Algal cells Protococcaceae or _Trentepohlia_. Apothecia sessile, more widely open than in the previous family; in some genera the thallus forms an outer apothecial margin. The genera _Farriola_ from Norway and _Tylophorella_ from New Granada are monotypic. The British genus _Cyphelium_ has been known as _Trachylia_. Thallus with Protococcaceae. Spores colourless, simple 1. *Farriola Norm. Spores brown, 1-3-septate (rarely simple or muriform) 2. Cyphelium Th. Fr. Thallus with _Trentepohlia_. Spores simple, many in the ascus 3. *Tylophorella Wainio. Spores 8 in the ascus. Apothecia with a thalline margin 4. *Tylophoron Nyl. Apothecia without a thalline margin 5. *Pyrgillus Nyl. XVII. _SPHAEROPHORACEAE_