Major Groups > Boletes > Leccinum


The Genus Leccinum and Leccinoid Fungi

[ Basidiomycota > Boletales > Boletaceae . . . ]

by Michael Kuo

The genus Leccinum has recently been broadly defined (Kuo & Ortiz-Santana 2020) in order to reflect how the mushrooms have evolved together, so there are now two distinct groups of mushrooms in the genus. The first group consists of underground, truffle-like fungi (for example Leccinum caespitosum) that were placed until recently in the genera Chamonixia, Octaviania, Rossbeevera, and Turmalinea. The second group, the one my friend Hoa calls the "sexy Lexies," contains boletes; the mushrooms are soft-fleshed mycorrhizal partners with trees, featuring tubes and pores on the underside of a cap that sits atop a central stem.

Unlike most other boletes, however, the stems of leccinoid mushrooms are punctuated with scabers, which typically become brown or black by the time the mushroom is mature—though in a few species the scabers are light in color, reddish, or nearly invisible to the naked eye. (If you are new to bolete identification, compare scabers carefully with glandular dots and reticulation). Aside from the scabrous stems, there is something particularly Leccinum-esque about leccinoid mushrooms; their stature and colors are somehow distinctive. But while recognizing that a bolete is a Leccinum is usually relatively easy, figuring out what species you have found can be truly frustrating. In fact, if you are a North American collector at this point in time, it may not be possible to identify many Leccinum species with scientific confidence.

One thing that is clear, however, is that Leccinum species are "host-specific," which means that they only associate with certain kinds of trees. Some species and groups of species appear to be pickier than others, but virtually none qualifies as an all-out "generalist," capable of associating with just about any tree. This means that would-be Leccinum identifiers will need to pay attention to the trees in the vicinity of their collections, because this information is likely to be essential in identifying the mushrooms.

Physical features that come into play with Leccinum identification include the color of the cap, as well as the color of the pore surface and whether it changes color when bruised. Color changes of the flesh, when sliced open, should also be noted—and these sometimes take quite a little while to manifest, so I recommend slicing a Leccinum in half lengthwise as you begin the process of taking notes, then observing it every five or ten minutes for at least half an hour. The margin of the cap, in many species, features a sterile overhanging portion that splits as the mushroom grows, creating little flaps of tissue; in other leccinoid mushrooms these flaps are missing. The color of the stem's scabers is important, ranging from nearly white to brown or black—and sometimes the color changes as the mushroom matures, so you will need both young and old specimens to assess this feature confidently.

Microscopic examination can provide useful data for Leccinum identification. The morphology of spores, hymenial cystidia, caulocystidia, and the pileipellis should all be recorded, using 2% KOH as a mounting medium. In the 1960s and 70s there was some interest in tissue reactions to Melzer's reagent, but these putatively important reactions have since been shown to be inconsistent and ultimately uninformative.

Pages for Leccinoid Fungi

Harrya chromapes
Hemileccinum hortonii
Hemileccinum subglabripes
Leccinum albellum
Leccinum caespitosum
Leccinum holopus
Leccinum longicurvipes
Leccinum quercophilum


Leccinum versipelle

Leccinum sp.

Leccinum albellum

Leccinum longicurvipes

Leccinum quercophilum


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Kuo, M. (2020, January). The genus Leccinum and leccinoid fungi. Retrieved from the MushroomExpert.Com Web site:

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