Flora of New Zealand Series

Type : Tremella mesenterica Schaeff.: Fr. typ. cons. 

Description : Basidiomata mostly cerebriform to foliose, 0.2–8 cm diam., distinct basidiomata lacking in species endoparasitic on other basidiomycetes or in hymenia of discomycetes, or for lichenicolous species, often growing within galls induced in the lichen host. Context thin- to thick-walled; clamp connections characteristic for most species, but lacking in several lichenicolous as well as non-lichenicolous taxa; haustorial branches frequent in fungicolous (including lichenicolous) species, often with clamp connections. Hymenium containing numerous probasidia that are sometimes intermixed with conidiogenous cells and/or hyphidia; probasidial initials subspherical, ellipsoidal or clavate, pyriform or sometimes stalked, capitate; proliferations occurring through the basal clamp; hyphidia absent or reduced, but in a few species forming a distinct hymenial layer; cystidia absent. Basidia when mature, (1–)2–4-celled, with longitudinal, oblique or transverse septa; epibasidia subcylindrical, elongate. Basidiospores subspherical to ellipsoidal, with a distinct apiculus. Anamorph often present; either conidiogenous cells producing single conidia, or producing numerous conidia, catenate conidia or asteroconidia.

Tremella, included in the family Tremellaceae (Chen 1998; Kirk et al. 2001; Lawrey & Diederich 2003; Diederich 2004j), in the order Basidiomycota, comprises at least 200 non-lichenicolous species and 46 lichenicolous taxa, of which one is presently known from New Zealand (from species of Ramalina). Species of Tremella are almost all parasitic on other fungi, including lichens and produce galls on their hosts. Two new lichenicolous taxa on species of Usnea were described in Diederich & Christiansen (1994), and more recently Diederich (1996) monographed the known lichenicolous species, giving a key and descriptions to 46 species. See also Etayo (2002), Sérusiaux et al. (2003) and Diederich (2003: 82–85). Species of Tremella occur on a wide variety of lichen genera including Anaptychia, Caloplaca, Candelariella, Cetraria, Cladonia, Coccocarpia, Dendrographa, Evernia, Graphidiastra, Haematomma, Hypocenomyce, Hypogymnia, Lecanora, Leptogium, Letharia, Lobaria, Mycoblastus, Nephroma, Normandina, Parmeliella, Parmotrema, Pertusaria, Phaeographis, Phaeophyscia, Physcia, Platismatia, Polymeridium, Protoparmelia, Pseudocyphellaria, Psoroma, Ramalina, Rhizocarpon, Rimelia, Rinodina, Sticta, Sulcaria, Trypethelium  Tuckermannopsis and Usnea. It is extremely likely that many more species will be found in New Zealand.