Fleshy Fungi of New Brunswick >> Crucibulum laeve

Crucibulum laeve (Huds.) Kambly

On dead leaves and twigs in mixed forest of Abies balsamea, Acer saccharum and Populus tremuloides, Nepisiguit Protected Natural Area, New Brunswick (20-08-16).

Basidiospores 6.4-9.4 X 3.7-4.6 μm, D/d = 1.58-2.12, ellipsoidal, smooth, inamyloid. Basidia 4-spored, borne within the peridioles ("eggs").

The basidia of C. laeve are unusual in having an apparent double wall. The outer wall is thick and possibly gelatinous. At maturity the inner layer breaks out through the apex of the outer one, leaving an annular ring or collar where the wall broke. The lower right panel of the illustration above shows six basidia in various stages of maturity. They have been stained with either Phloxine (pink) or Congo Red(orange-red). The "collar" marking the point of separation between the two walls is rather faint in these photos but can be seen near the top in most of the basidia. This "Jack-in-the-Box" mechanism is reminiscent of the bitunicate ascus, characteristic of the Dothideomycetes, although they are not at all closely related to these bird's nest fungi.

Photo: D. Malloch (20-08-16).