Agaricus lanatoniger

A. lanatoniger was first described in 1974 by Belgian mycologist Paul Heinemann and collected by Egon Horak in December 1967.[1] The holotype specimen was collected in the Westland Province, of New Zealand by Lake Haupiri, underneath red beech (Nothofagus fusca) and rimu (Dacrydium cupressinum) trees.[1] The original paper reference number was incorrect,[2] but is correctly listed as PDD 27107 in a report on New Zealand Agaricus species in 1999.[3]

The pileus of Agarcius lanatoniger can vary from a spherical to a convex shape.[1] Smaller specimens tend to have more spherical pileus, while larger are more flattened convex shape, although both have round shape when viewed from above. The dark brown, felt-like pileus or cap can be up to 120 mm (4.7 in) wide in diameter.[1]

The gills consist of thin pink filaments, stemming from the underside of the pileus without touching the stem.[1] This forms a small ring around the stem less than 1 mm (0.039 in) long. About a third of the length of the stem is a 1 mm (0.039 in) thick skirt. This extends 10 mm (0.39 in) out from the stem. Above the skirt, the stem is tan or pale colour.[1] While underneath, the colour transitions from light brown to dark brown or black like the cap's colour.[1]

The stem ranges from 30 to 50 mm (1.2 to 2.0 in) in length and with a diameter of 12–14 mm (0.47–0.55 in), generally thicker toward the base. Inside the stem is a white, hollow column beginning at gill level but sealed at the bottom. Beneath the ground, the bulbous shape has many small root-like filaments. The stem's insides are white with a hollow center.[1]

The sequence of A. lanatoniger, when compared to A. purpureoniger differed only by one nucleotide,[4] suggesting that they be the same species. When physically compared, the A. purpureoniger is more purple.[5] However, over the last three decades, all samples of A. purpureoniger have been found in similar locations as A. lanatoniger, specifically in the northwestern regions of both the New Zealand islands.[6][7]

Agaricus lanatoniger has been found in nine different terrestrial locations primarily in New Zealand[7] The mean annual temperature for all locations ranges from 6.98–15.10 °C (44.56–59.18 °F).[7] Due to New Zealand's temperate climate, this fluctuates throughout its four distinct seasons. Most samples show A. lanatoniger in the ground of forests, however, the type of forest has not been noted.[7]

Lanatoniger originates from the Latin "lanatus" (adj) meaning wooly or downy.[8] This refers to the felt-like texture of its pileus.