Multiclavula ichthyiformis

Multiclavula ichthyiformis is a species of terricolous (ground-dwelling) basidiolichen in the family Hygrophoraceae. Found in Costa Rica, it was formally described as a new species in 2007 by Matthew Nelsen, Robert Lücking, Loengrin Umaña, Marie Trest, and Susan Will-Wolf. The type collection was collected in the Macizo de la Muerte section of Tapantí National Park (Cartago Province) at an elevation of 2700 m. Here, in a disturbed high-altitude peat bog in a rainforest, it was found growing on the ground along a brook and a road bank.

The thallus of Multiclavula ichthyiformis is barely discernible as a greenish layer on the soil up to 5 cm across, containing colonies of green algae (the photobiont, from the genus Coccomyxa)) and fungal hyphae. The fruit bodies are fleshy, unbranched, and lanceolate, with a fishtail-like lamina. The species epithet ichthyiformis refers to this latter feature. Its basidiospores are smooth and spherical, thin-walled and hyaline, and measure 4–6 μm in diameter. Other ground-dwelling lichens that were prevalent in this habitat included Cladia aggregata, Cladonia confusa, Dictyonema glabratum, Icmadophila aversa, Phyllobaeis imbricata, and Siphula ceratites.