Microglossum rufum

Description

Microglossum rufum is a small mushroom with an orange to the yellow club-shaped fruiting body. The enlarged, fertile “head” or spore sac has a pore at the tip through which the mature spores are forcibly ejected into the air. The “head” is slightly flattened. The stem is cylindrical. Under a microscope the spores are colorless. Grows are scattered or clustered together in sphagnum moss, on rotting logs, and in leaf litter throughout North America.

This species is sometimes confused with Cordyceps militaris. C. militaris, however, has dark orange bumps (i.e., perithecia necks) embedded in the orangish head and if dug up carefully, will be found attached to the larva of a butterfly or moth.

Common names: Orange Earth Tongue, Yellow Earth Tongue.

Mushroom Identification

1. Ecology

   Traditionally reported as saprobic; growing alone to gregariously in various forests types, on the ground, in humus, among mosses, or from very well-rotted wood; summer and fall; widely distributed in North America east of the Rocky Mountains and Mexico, but not in tropical areas; also reported from Australasia and Japan.

2. Fruiting Body

   20–50 mm high and 2–5 mm wide; club-shaped to somewhat flattened and irregular; head and stem separated.

3. Head

   4–19 mm high; 3–8 mm across; widely flattened-fusiform at first, developing a central longitudinal crease and becoming "Croatia-shaped"; bald; orange-yellow to yellow.

4. Stem

   7–35 mm high; 1–3 mm thick; more or less equal; scaly; orangish yellow to yellow.

5. Flesh

   Yellowish; unchanging when sliced.

6. Odor

   Not distinctive.

7. Microscopic Features

   Spores 30–35 x 4–5 µm; cylindric to suballantoid; smooth; with one to several large oil droplets; hyaline in KOH; developing 5–10 septa. Asci 120–140 x 7.5–12.5 µm; cylindric; smooth; hyaline KOH; with amyloid tips. Paraphyses 140–160 x 2–3 µm; filiform-cylindric; curved about 60–90 degrees once clear of the asci; apices subclavate or merely rounded; smooth; hyaline in KOH.

Synonyms

1. Ochroglossum rufum (Schwein.) S. Imai 1955

2. Geoglossum rufum Schwein. 1832

Photo sources:

Photo 1 - Author: Nathan Wilson (CC BY-SA 3.0)

Photo 2 - Author: Jason Hollinger (CC BY-SA 2.0)

Photo 3 - Author: Jimmie Veitch (jimmiev) (CC BY-SA 3.0)