Names: Amygdalaria, Almond Lichens
Description: Crustose lichens, most often with a thick, areolate thallus; exiple brown-black; asci Porpidia-type
Color: Pinkish or brownish to creamy tones.
Cephalodia: Almost always present containing one of several types of cyanobacteria, sometimes on the same thallus.
Photobiont: Main one is green (unicellular).
Apothecia: Contains black, immersed disks, like Aspicilia.
Spores: Large, almond-shaped, halonate.
Chemistry: Gyrophoric acid & the stictic acid complex are the most common.
Substrate: On siliceous rocks.
Habitat: Mainly humid, oceanic habitats; some are arctic.
Lookalikes: Amygdalaria is distinguished from Porpidia mainly in having cephalodia, larger spores with a compact, conspicuous halo, & more often immersed apothecia. It is also associated with humid, oceanic habitats. Related genera with Porpidia-type asci, halonate spores, & immersed apothecia include Bellemerea & Immersaria, both of which lack cephalodia. Bellemerea has brown apothecial disks, a colorless exciple, & smaller spores. Immersaria carbonoidea is a rare lichen from arctic Alaska with a dark brown, arcolate thallus, black apothecial disks often clustered in groups, a brown epihymenium, & a dark brown hypothecium & exciple. Its spores are 13 – 13 x 6.5 – 7.5 um, & the thallus mudulla is PD-, K-, C-, IKI+ blue.
Bibliography: Lichens of North America, by Brodo, Sharnoff, & Sharnoff
Database Entry: Distance Everheart 12-26-13