Butyriboletus yicibus

What the name records

Butyriboletus yicibus was named by D. Arora and J.L. Frank in 2014, when the butter boletes were moved into the genus Butyriboletus as a molecularly and morphologically distinct group. The epithet joins Yi, for the Yi people of Yunnan, and the Latin cibus, food. The English name Yi butter bolete is a convenience name from a modern secondary page; it is not a verified local name. The 2026 Chinese catalogue uses 彝食黄肉牛肝菌.

Species Fungorum lists the name as accepted, and no synonym was found in the sources checked.

The fungus as described

The protologue describes medium-sized fruitbodies with a brown cap, a yellow pore layer that usually bruises blue-grey, a slender yellow reticulate stem, and firm, mild flesh that may stain blue-grey slowly or unevenly.

The description separates it from the Yunnan species B. sanicibus by its more slender habit and blue-grey rather than blue staining, and from B. roseoflavus by the lack of red cap tones. These are scientific description features. They are not a field key, and a bruising reaction or a market label does not identify a specimen.

Habitat and season

The type was collected on 3 August 1997 in Lijiang County, Yunnan, scattered in a Pinus yunnanensis forest on the road from Lijiang to Jade Dragon Snow Mountain. The protologue gives a July to September fruiting window. That is a reported window from the source, not a measured annual season for the region.

Later sequence studies cite further vouchers from Yulong, Yunnan. The original paper remains the clearest primary account of the type locality and habitat.

Food use and the limits of that claim

The food record rests on three things: the protologue's report of Yi use in Lijiang, the 2026 catalogue marking the species edible, and China CDC outbreak tables that list it as edible. The protologue examined one collection, and its attribution to Naxi and Bai people is explicitly tentative. The catalogue is a checklist, not a consumption study.

China CDC tables list B. yicibus with Neoboletus venenatus in mixed dried-bolete incidents. In a 2022 Hunan incident, two patients were reported, with no deaths. The tables record the co-occurrence and do not attribute illness to B. yicibus. The authors note that edible mushrooms can appear in incidents involving mixed mushrooms, contamination or individual susceptibility.

The sources do not give a safe preparation, a cooking time or a dose. An edible label, a blue reaction or a sold dried product does not establish that a given specimen is safe. Do not identify a wild bolete for eating from this page; several boletes have regional look-alikes with different toxicology.

Images and gaps

The public gallery includes a labelled photograph of the dried type voucher and four explicitly labelled comparisons from the same genus. Those comparison photos show different species, not B. yicibus. The hero is an original illustrative reconstruction based on the published description, not a photographed or identified specimen.

A source-linked contextual photograph from the protologue is retained in the gallery history, but its public thumbnail failed to render. Its published caption describes Yi women with B. yicibus and Lactarius sp. None of these images supports field identification or edibility.