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
The most highly evolved family of the subseries, as regards the thallus. Algal cells Protococcaceae. In Tholurna, a small lichen endemic in Scandinavia, there is a double thallus: one of horizontal much-divided squamules, the other swollen, upright, terminating in the capitulum. The fruit is lateral in Calycidium, a squamulose form from New Zealand, and in Pleurocybe from Madagascar, with stiff strap-shaped fronds. All the genera are monotypic except Sphaerophorus, of which genus ten species are recorded, some of them with a world-wide distribution. The spores are brown and simple or 1-septate.
| Thallus squamulose and upright | 1. | *Tholurna Norm. |
| Thallus wholly squamulose | 2. | *Calycidium Stirton. |
| Thallus fruticose. | ||
| Fronds hollow in the centre | 3. | *Pleurocybe Müll.-Arg. |
| Fronds not hollow. | ||
| Fruit without a thalline margin | 4. | *Acroscyphus Lév. |
| Fruit inclosed in the tip of the fronds | 5. | Sphaerophorus Pers. |
Subseries 2. Graphidineae
In this subseries are included five families that differ rather widely from each other both in thallus and apothecia; the latter are more or less carbonaceous and mostly with a proper margin only. Families and genera are widely distributed, though most abundant in warm regions. Algal cells mostly Trentepohlia.
A comprehensive study of the apothecia of this series by Bioret[1044] gives some interesting results in regard to the paraphyses: in Arthonia they are irregular in direction and much-branched; in Opegrapha, the paraphyses are vertical and parallel with more regular branching; Stigmatidium (Enterographa) resembles Opegrapha in this respect as does also Platygrapha, a genus of Lecanactidaceae, while in Graphis the paraphyses are vertical, unbranched and free; Melaspilea paraphyses are somewhat similar to those of Graphis.