Rickenella

Rickenella is a genus of small, saprophytic fungi in the family Agaricaceae (formerly Mycenaceae or Hemimycenaceae). They are generally found growing on decaying plant matter, especially mosses, liverworts, and leaf litter.

Description:

Fruiting Body: Rickenella species typically have small, delicate fruiting bodies with a cap diameter ranging from a few millimeters to about a centimeter. The cap shape can be convex, campanulate (bell-shaped), or flattened, often becoming depressed with age. The color of the cap varies depending on the species, and can include shades of white, cream, yellow, orange, brown, or gray.

Gills: The gills are typically adnate (attached to the stem) or decurrent (running down the stem), and are often widely spaced. Their color is usually similar to the cap, but can be paler.

Stem: The stem is thin and wiry, often translucent, and usually the same color as the cap or gills. It is typically central in its attachment to the cap.

Spores: The spores are hyaline (translucent) and smooth, and often amyloid (staining blue-black in Melzer's reagent).

Microscopic Features: Microscopic examination is often necessary for accurate identification of Rickenella species, focusing on features such as the shape and size of the spores, the presence or absence of cystidia (specialized cells on the gill edge or surface), and the structure of the pileipellis (cap surface).

Ecology and Distribution:

Rickenella fungi are saprophytic, meaning they obtain nutrients from decaying organic matter. They play an important role in nutrient cycling in their respective ecosystems. They are commonly found in damp, shaded environments, such as forests and bogs, where there is an abundance of decaying plant material. The genus has a widespread distribution, occurring in various regions of the world, including Europe, North America, and Asia.

Taxonomy:

The taxonomy of Rickenella has been subject to revision over time. Molecular studies have helped to clarify the relationships between species and related genera. The genus is named after the German mycologist Adalbert Ricken.

Identification:

Identifying Rickenella species can be challenging due to their small size and subtle differences. Careful observation of macroscopic features, combined with microscopic examination, is generally required for accurate identification. It is important to consult with reliable field guides and mycological resources to confirm identification.