Tylopilus indecisus

Description

Tylopilus indecisus is a bolete fungus in the family Boletaceae native to North America. This robust bolete has a brown cap, reticulate stipe, and pale-colored pores, features that could lead to confusion with Boletus edulis (king bolete) and Boletus regineus (queen bolete).

The California species going under the name "Tylopilus indecisus" (see Thiers, 1975; Desjardin, Wood & Stevens, 2016) is not the species originally described by Peck from New York state in 1888; it is more robust, bruises much more readily, and possesses a much more reticulate stem. It is associated with coastal hardwoods and probably represents an officially undescribed species.

It was described in 1888 by Charles Horton Peck.

Mushroom Identification

1. Ecology

   Mycorrhizal with oaks, and possibly other hardwoods; growing scattered or gregariously; summer; widely distributed east of the Rocky Mountains.

2. Cap

   5–11 cm; convex when young, becoming broadly convex or nearly flat in age; dry; very finely felty to bald; medium brown to tan.

3. Pore Surface

   Beige, becoming pinkish and, eventually, pinkish-brown; bruising brown; pores circular to angular, 1–3 per mm; tubes to 15 mm deep.

4. Stem

   3–7 cm long; 1.5–2 cm thick; more or less equal; whitish overall when young, developing brownish stains and sometimes becoming brownish with development; usually finely reticulate near the apex, but occasionally not reticulate; bald; basal mycelium white.

5. Flesh

   White; soft; staining pinkish to brownish in places when sliced.

6. Odor and Taste

   Not distinctive.

7. Chemical Reactions

   Ammonia negative on cap surface; negative on flesh. KOH dark red to dark gray or black on cap surface; yellowish to orangish on flesh. Iron salts blue-gray to gray on cap surface; negative to pale bluish-gray on flesh.

8. Spore Print

   Brownish pink to pinkish brown.

9. Microscopic Features

   Spores 10–15 x 3.5–5 µm; smooth; fusiform to subfusiform; smooth; hyaline to yellowish in KOH. Hymenial cystidia 25–75 x 5–15.5 µm; fusoid-ventricose, often with long necks; hyaline to golden in KOH; smooth. Pileipellis a collapsing, tangled trichoderm; hyaline to brownish or golden in KOH; terminal cells cylindric with rounded or subacute apices, 2.5–5 µm wide.

Photo sources:

Photo 1 - Author: walt sturgeon (Mycowalt) (CC BY-SA 3.0)

Photo 2 - Author: Ron Pastorino (Ronpast) (CC BY-SA 3.0)

Photo 3 - Author: Ken Stavropoulos (pennybun) (CC BY-SA 3.0)