Schizotrema
Schizotrema is a genus of lichen-forming fungi in the family Graphidaceae. The genus was circumscribed in 2009 by Armin Mangold and H. Thorsten Lumbsch.
Description
The genus Schizotrema consists of lichens with a thallus that can range from being in the to appearing more superficial. The thallus is usually pale in colour and often inconspicuous. Its photosynthetic partner, or, is a green alga from the genus Trentepohlia. The, a structure that sometimes surrounds the edges of the lichen, is faint and brown, blending subtly with the substrate. Some species produce soralia, which are small, discrete, and structures that release powdery reproductive propagules for asexual reproduction.The ascomata, or sexual reproductive structures are generally rounded and embedded within the thallus. These structures are surrounded by a thick, layered, which may flake away as the lichen ages. The, the tissue surrounding the spore-producing region, is dark brown to black and multilayered. It may or may not react with iodine at its base and is lined with small hair-like structures known as.
Internally, the hymenium is tightly packed and does not react to iodine staining. The, the network of sterile filaments within the hymenium, is composed of unbranched paraphyses with tips that are not thickened. The asci, which are sac-like structures where spores develop, are and contain between one and eight spores. These asci also do not react to iodine. The spores produced by Schizotrema are transversely septate or . They are hyaline to yellowish, sometimes becoming brown at full maturity, and may have a thin gelatinous coating. Asexual reproductive structures called conidiomata have not been observed to occur in this genus.
Species
- Schizotrema flavolucens
- Schizotrema guadeloupense
- Schizotrema quercicola
- Schizotrema schizolomum
- Schizotrema subzebrinum – New South Wales
- Schizotrema vezdanum – Tasmania
- Schizotrema zebrinum – New South Wales