''Caloboletus marshii'', commonly known as Ben's bitter bolete, is a species of

mushroom A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is ...

in the family

Boletaceae The Boletaceae are a family of mushroom-forming fungi, primarily characterised by small pores on the spore-bearing hymenial surface (at the underside of the mushroom), instead of gills as are found in most agarics. Nearly as widely distributed ...

. It is not poisonous, but it is too bitter to eat. It turns blue when cut or bruised, and it grows under

live oak Live oak or evergreen oak is any of a number of oaks in several different sections of the genus ''Quercus'' that share the characteristic of evergreen foliage. These oaks are not more closely related to each other than they are to other oaks. ...

Taxonomy

''Caloboletus marshii'' was first unofficially described by David Arora as ''Boletus "marshii"'' in his book Mushrooms Demystified, which was first published in 1979 and later revised in 1986. In 2014, Jonathan L. Frank formally described the species as ''Caloboletus marshii''.

Description

The cap of ''Caloboletus marshii'' is about 2-6 inches (6-15 cm) across, and the stipe is about 1-4 inches (3-10 cm) long and 0.7-4 inches (3-10 cm) wide. The pore surface and the flesh are yellow, and quickly turn blue when bruised or cut.

Similar species

''Caloboletus marshii'' can be confused with the brown butter bolete, '' Butryiboletus persolidus.'' It can also be confused with the white king bolete, '' Boletus barrowsii'', which doesn't bruise blue as much as ''Caloboletus marshii''.

Habitat and ecology

''Caloboletus marshii'' is a mycorrhizal fungus that grows under live oaks in

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the ...

Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idah ...

, and Washington. It fruits in late summer and fall, often before the rains come. It is rarely found fruiting in November.

Edibility and discovery

''Caloboletus marshii'' is inedible due to its extremely bitter taste. However, this didn't stop a man named Ben Marsh from repeatedly trying to make it edible. This brought the mushroom to David Arora's attention, and he named it after Ben Marsh.

References