On the underside of the cap are a crowded array of tiny tooth-shaped protrusions ("teeth") up to 3 mm long; they are initially whitish to purplish-pink before turning brown in age.

Fruit bodies change their geotropic response three times during their development, which helps ensure that the teeth ultimately point downward for optimum spore release.

The pure culture, cell division and the ultrastructure of A. vulgare's hyphae and mycelia have been studied and described in search of potentially useful characters for phylogenetic analysis.

Although common, its small size and nondescript colors lead it to be easily overlooked in the pine woods where it grows.

[9] Despite vast differences in appearance and morphology, A. vulgare is related to such varied taxa as the gilled fungi of Lentinus, the poroid genus Albatrellus, the coral-like Clavicorona, and fellow tooth fungus Hericium.

It attaches to the side of the cap and is cylindrical or slightly flattened with a bulbous base, 2–8 cm tall and 1–3 wide.

[13] The stem is similarly divided, with a thin, dark and hairy cortical layer covered by hairs, which encircles inner ochre-colored flesh.

Viewed under a light microscope, the spores appear hyaline (translucent), covered with minute wart-like bumps, and are spherical or nearly so, with dimensions of 4.6–5.5 by 4–5 μm.

The cortex (the tougher outer layer of flesh) is made of parallel unbranched generative hyphae that are brown, thick-walled, clumped together, and frequently clamped.

Gloeoplerous hyphae (containing oily or granular contents) are also present, protruding into the hymenium as club-like or sharp-pointed gloeocystidia.

In an effort to determine ultrastructural characters useful for systematic and phylogenetic analyses of the Agaricomycotina, Gail Celio and colleagues used electron microscopy to examine both the structure of the septal pore, and nuclear division in A. vulgare.

Due to the scarcity of similar data from other Agaricomycotina species, it is unknown whether the extended septal pore cap margins of A. vulgare are phylogenetically informative.

Spherical spindle pole bodies containing electron-opaque inclusions are set within gaps on opposite ends of the nuclear membrane.

Although the fruit body takes at least 9 days to mature, spores production begins within 48–72 hours of the start of cap growth.

These secondary growths typically number between four and seven; some may be aborted as the nutrients from the pine cone substrate are depleted, resulting in stems lacking caps.

Removal of incompletely mature laboratory-grown specimens from a relative humidity (R.H.) of over 98% to one of 65–75% causes the fruit bodies to brown and stop growing.

[18] One author noted finding the mushroom on spruce needles on top of squirrel dens where cone bracts were present in the forest floor.

[27] In a study conducted in the Laojun Mountain region of Yunnan, China, A. vulgare was found to be one of the most dominant species collected from mixed forest at an altitude of 2,600–3,000 m (8,500–9,800 ft).

[31] In North America, its range extends from Canada[27] to the Trans-Mexican Volcanic Belt south of Mexico City.

[32] The mushroom is common, appearing in the summer and autumn,[13] although it is easily overlooked because of its small size and nondescript coloration.

The colonies that grow are white to pale cream, and cover the agar surface within six weeks from the initial inoculation.

The zones appear somewhat lighter in color because the hyphae are more closely packed and form crystalline substances that deposit into the agar.