Fleshy Fungi of New Brunswick >> Rickenella fibula

Rickenella fibula (Bull.) Raithelh.

Gregarious amongst gametophytes of Rhytidiodelphus subpinnatus in moist and shady area of a rural lawn, associated with Abies balsamea, Little Lepreau, New Brunswick (12-08-18/01).

Basidiospores white in spore print, variable in shape but mostly narrowly ellipsoidal, frequently concave on the ventral side, smooth, inamyloid, 5.0-6.6(7.2) x 2.9-4.0 µm, Q = 1.39-1.91 (average[35]: 5.8 x 3.4 µm, Q = 1.70). Basidia 4-spored, with a basal clamp connection. Hymenial cystidia scattered but frequent, ventricose-rostrate, often swollen at the apex, thin-walled, 44-78 x 8.6-11.9 µm. Pileipellis a cutis, bearing numerous cystidia similar to those of the hymenium.

This tiny mushroom is easily recognized by its bright orange cap, white decurrent gills and its growth on mosses. The large cystidia covering the cap and stipe are visible with a hand lens as minute spines. Under a microscope the shape of the cystidia and the small non-amyloid basidiospores are also diagnostic. There is a white form of this species that has been described as a variety, but is now rarely even given that recognition.

Photograph: D. Malloch (12-08-18/01).