Fleshy Fungi of New Brunswick >> Tricholoma vaccinum

Tricholoma vaccinum (Schaeff.) P. Kumm.

Gregarious (8) in a Pleurozium schreiberi carpet with some Dicranum spp, associated with Abies balsamea and Picea mariana, Little Lepreau, New Brunswick (05-10-19/01).

Basidiospores white in spore print, hydrophilic, broadly ellipsoidal, hyaline, smooth, unchanging in Melzer’s Solution, 5.0-6.4 x 3.9-4.9 μm, Q = 1.22-1.47 (average[28]: 5.6 x 4.3 μm, Q = 1.30). Hymenial cystidia lacking. Basidia 4-spored, without basal clamp connections. Pileipellis a loose cutis with some ascending fascicles that form the scales, of orange brown unencrusted (or maybe very finely encrusted) clampless hyphae, without a well-differentiated subpellis.

Tricholoma vaccinum, as defined by most collectors, is a variable taxon that is difficult to characterize precisely. It is recognized by its dry brown scaly pileus, variously scaly stipe and by its white flesh having a farinaceous or cucumber like odour and taste. Microscopically it is characterized by a lack of both clamp connections and gelatinous tissues. Its apparent variability may be because several species are being lumped under one name. NB: the colour in the field photo here is not accurate but does show the scales of the pileus better than the scan. On the other hand, the colours in the scan match those in the field notes closely.

Genetic studies are needed to sort this variability out. The Mycoquebec web site includes 26 collections under T. vaccinum, highly variable in appearance. Our Collection 05-10-10/01 looks most like one labeled MQ18R228, photographed by Jacques Landry. The site also contains some molecular information about 7 Quebec collections and groups them into two clades. MQ18R228, collected near Radisson, Quebec, falls into what is described as the "clade européen".

Photograph: D. Malloch (05-10-19/01).