In this guide, we’ll cover common features of the bolete family, describe the three largest genera of the boletes, and talk about the characteristics of the types of bolete mushrooms in each genus. So, without further ado, let’s jump in!
Common Characteristics of the Bolete Family
The first major defining characteristic of boletes is that they lack gills. Instead of gills, these stipe and cap fungi have spongy pores as their spore dispersal tissue. The caps of these mushrooms are also often spongy and greasy. These mushrooms are almost exclusively mycorrhizal, meaning they derive their nutrients from forming a symbiotic plant-fungi relationship with trees. Additionally, the stipes of all boletes are centrally located under their caps. They’re all forest-inhabiting fungi, with no species known to grow in open meadows or fields.
Three Main Types of Bolete Mushrooms
The common name “bolete” describes the fungi across the Boletaceae family rather than a single genus. As such, it’s easier to separate boletes into “types” based on what genus they’re classified into. While four new genera of boletes were described by researchers in 2015, we’ll focus in this guide on the three main genera:
LeccinumSuillusTylopilus
Note, many species are still classified into the genus Boletus, but this classification is under debate since the original, singular genus of Boletus is being increasingly re-classified into new genera based on macroscopic and microscopic morphologies and DNA analysis.
Leccinum
Boletes in the genus Leccinum are commonly known as scaber stalk boletes. This name refers to the mottled, brown-black markings on the stipes of these boletes. Due to this characteristic, it’s generally easy to narrow down boletes with these markings into the Leccinum genus. It’s important to note that a few species of Leccinum have paler or more reddish scabers. The boletes of this genus are notably hefty. So, Leccinum boletes are also sometimes called aspen or birch boletes due to their affinity with establishing mycorrhizal relationships with these trees. Boletes of this genus are particularly popular cuisine in Eastern Europe where they are plentiful. Within the past decade, however, poison control centers have been collecting reports of poisonings by Leccinum boletes, particularly orange-capped Leccinum boletes. Most cases have been gastrointestinal distress, but at least one case has emerged of internal bleeding in an elderly patient. Some modern field guides are shifting to cautioning foragers against collecting scaber-stalked boletes or from collecting orange-capped specimens.
Suillus
The next genus of boletes we’ll cover is Suillus. This genus of boletes is known for having particularly slimy caps. If you ever take a stroll in the forest, come across a bolete, and are immediately grossed out by how slimy the cap is, it’s likely a species in the Suillus genus. You’ll likely be strolling through a temperate coniferous forest across Northern Hemisphere if you spot one of these guys, as these boletes have a particular affinity for growing under conifers. These types of bolete mushrooms typically have glandular dots on the stipe, which are collections of small pigmented cells that appear as dots. These glandular dots are often off-white or pale in color, making them difficult to spot at first glance. This is in comparison with the conspicuous dark mottling of scabers on Leccinum species. One unique feature of the Suillus genus of boletes is that they have partial veils. As such, it’s easy to identify mature Sullius bolete by the presence of a ring of thin membranous tissue around the stipe. Young specimens will have the underside of the cap covered by the veil. Additionally, the pores of this genus are notably larger and more radial than other genera of the bolete family.
Tylopilus
The final genus of boletes we’ll be covering is the Tylopilus genus. Species in this genus mostly grow in temperate areas of Asia, although there are some North American species as well. A defining feature of this genus is that most species have pink-tinted pore surfaces. This pink coloration is generally more distinct on mature species, while young species tend to have paler pore surfaces, which can confuse identification. The stipes of this genus do not have partial veils. You’ll often note that the cap colors of young species of this genus are quite vivid, though color can vary. The cap colors tend to fade as the mushrooms ages, often into a vague tan or brown color.
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