Compositrema isidiofarinosum
Compositrema isidiofarinosum is a species of corticolous crustose lichen in the family Graphidaceae. This lichen was discovered in Puerto Rico. It flourishes in the shaded understory of the palo Colorado forest in El Yunque National Forest, clinging to the trunks of unidentified trees.
Taxonomy
Compositrema isidiofarinosum was first scientifically described in 2014 by lichenologists Joel Mercado-Díaz, Robert Lücking, and Sittiporn Parnmen. The species name, isidiofarinosum, hints at one of its unique characteristics: a powder-like, thallus. The type specimen was discovered by the first author on a tree trunk in Canóvanas, Puerto Rico, specifically in Barrio Cubuy, on the trail leading to Pico del Toro.Description
Compositrema isidiofarinosum is a lichen species with a powdery, continuous thallus that measures up to in diameter. Its surface is light greenish white, adorned with sparse, scattered, corticate isidia, which are tiny, outgrowth-like propagules that aid in reproduction. The presence of these isidia, along with the relatively small ascomata and an inconspicuous, set it apart from other species in Compositrema.The lichen's is Trentepohlia, a genus known for its distinctive yellow-green cells. The asci are spindle-shaped to club-shaped, and each typically contains eight. These spores are hyaline, ellipsoid, and three times longer than wide with dimensions of 12–15 by 5–6 μm.
In terms of secondary metabolites, Compositrema isidiofarinosum produces psoromic acid and the related substances subpsoromic acid and 2'-O-demethylpsoromic acid.