2. Perichæna Fries
- 1817. Perichaena Fries, Symb. Gast., p. 11.
Sporangia flattened, sometimes small and roundish, more often larger, polygonal by mutual interference, or irregular, the peridium thickened outwardly by a dense reddish or brownish layer of scales; dehiscing by circumscission or by a lid; capillitium often scant, of slender, warted, yellowish threads, attached betimes to the upper wall; spores yellow, oval or spherical.
Key to the Species of Perichæna
| A. Sporangia plainly flattened. | ||
| a. Very flat, sporangia 1mm. or more in width | 1. P. depressa | |
| b. Depressed; sporangia smaller | 2. P. quadrata | |
| B. Sporangia more or less spherical | ||
| a. Chestnut brown | 3. P. corticalis | |
| b. Gray or canescent | 4. P. marginata | |
1. Perichaena depressa Libert.
[Plate XVII]., Fig. 10.
- 1837. Perichaena depressa Lib., Fl. Crypt. Ard., IV., No., 378.
Sporangia sessile, applanate, crowded, polygonal by mutual contact, fuscous or chestnut brown, shining, opening by a definite lid; spore-mass and capillitium yellow, the capillitium well developed, of slender yellow threads of various widths, almost smooth; spores minutely warted, 10–12 µ.
Easily recognized by the peculiar, polygonal, depressed-flattened sporangia and consequent shallow spore-cases in which lie the yellow spores and scanty capillitium. Rostafinski refers here P. vaporaria Schw., No. 2311, but the meagre description seems rather to apply to the next species. The original material is no longer accessible.