Fleshy Fungi of New Brunswick >> Lactarius tabidus

Lactarius tabidus Fr.

Clustered (2) in soil in a mature hardwood forest dominated by Acer saccharum, A. rubrum, and Betula alleghaniensis, locally associated with Cornus cornuta and Abies balsamea, Hell’s Gate Hardwoods Protected Natural Area, New Brunswick (14-09-19/04).

Basidiospores pale yellow to nearly white in spore print, broadly ellipsoidal, with amyloid warts separate to forming some connecting lines, 5.9-7.5 X 5.0-5.8 µm, Q = 1.15-1.31 (average[28]: 6.9 X 5.6 µm, Q = 1.23). Hymenial cystidia scattered along the sides and edges of the lamellae, ventricose-lanceolate. Pileipellis a very thin cutis to trichodermium, arising from a thick subpellis of subglobose cells.

Lactarius tabidus is a relatively small species of Lactarius with latex that appears to be white but which turns the flesh yellow as it dries. It is probably often mistaken for L. subducis or other small species with latex that does not change colour. This can be checked by drawing of some of the latex onto white filter paper or paper towel, as seen in the plate here, to look for the yellow colour as it dries. Microscopically the species is characterized by the thick subpellis of round cells giving rise to the very thin layer of surface hyphae.

Lactarius tabidus, as collected in North America, has probably often been mistaken for L. theiogalus, now generally considered to be a synonym of L. chrysorrheus. It is also possible that our North American collections represent a species not known in Europe, but so far we have insufficient evidence to use a non-European name.

Photo: D. Malloch (14-09-19/04).