In the form of the fruit, this family stands between Pyrenocarpeae and Gymnocarpeae, though more akin to the latter. Perforaria, with two species, belongs to New Zealand and Japan. Pertusaria has a world-wide distribution, and Varicellaria, a monotypic genus, with a very large two-celled spore, is an Alpine plant, recorded from Europe and from Antarctic America.
| Spores simple. | ||
| Apothecia with pore-like opening | 1. | *Perforaria Müll.-Arg. |
| Apothecia with a wider opening | 2. | Pertusaria DC. |
| Spores 1-septate | 3. | Varicellaria Nyl. |
XLV. Lecanoraceae
Thallus mostly crustaceous, occasionally squamulose or very rarely minutely fruticulose. The squamulose thallus is corticate above, the under surface appressed and attached to the substratum by penetrating hyphae, often effigurate at the circumference. Algal cells Protococcaceae. Apothecia well distinguished by the thalline margin; spores colourless, simple or variously septate or muriform.
Lecanora, Ochrolechia, Lecania, Haematomma and Phlyctis are cosmopolitan genera, some of them with a very large number of species; the other genera are more restricted in distribution and generally with few species.
The genus Candelariella is of uncertain position; the spores are 8 or many in the ascus and are simple or 1-septate, and not unfrequently become polarilocular as in Caloplacaceae, but there is no parietin present.
| Algae distributed through the thallus. Spores simple | 1. | *Harpidium Koerb. |
| Algae restricted to a definite zone. | ||
| Spores simple. | ||
| Thallus grey, white or yellowish. | ||
| Spores rather small | 2. | Lecanora Ach. |
| Spores large | 3. | Ochrolechia Massal. |
| Thallus bright yellow. | ||
| Spores simple or 1-septate | 4. | Candelariella Müll.-Arg. |
| Spores 1-septate (rarely pluri-septate). | ||
| Paraphyses free. | ||
| Thallus squamulose, effigurate | 5. | Placolecania Zahlbr. |
| Thallus crustaceous. | ||
| Apothecial disc brownish | 6. | Lecania Zahlbr. |
| Apothecial disc flesh-coloured | 7. | Icmadophila Trevis. |
| Paraphyses branched, intricate | 8. | *Calenia Müll.-Arg. |
| Spores elongate, pluri-septate. | ||
| Apothecia superficial | 9. | Haematomma Massal. |
| Apothecia immersed. | ||
| Paraphyses free | 10. | *Phlyctella Müll.-Arg. |
| Paraphyses branched, intricate | 11. | *Phlyctidia Müll.-Arg. |
| Spores muriform. | ||
| Apothecia superficial | 12. | *Myxodictyon Massal. |
| Apothecia immersed | 13. | Phlyctis Wallr. |
XLVI. Parmeliaceae
A very familiar family of foliose lichens. Genera and species are dorsiventral and stratose in structure, though some Cetrariae are fruticose in habit. Algal cells are Protococcaceae; in Physcidia they are Palmellae. In every case the upper surface of the thallus is corticate and generally of plectenchyma, the lower being somewhat similar, but in Heterodea and Physcidia, monotypic Australasian genera, the upper cortex is of branching hyphae parallel with the surface, the lower surface being non-corticate.