Variable-stalk Bolete

(Boletus variipes)

Conservation Status
Variable-stalk Bolete
Photo by AGShep
  IUCN Red List

not listed

 
  NatureServe

NNR - Unranked

 
  Minnesota

not listed

 
           
           
           
           
           
           
           
 
Description
 
 

Variable-stalk Bolete is a common, large, woodland mushroom. It occurs in the eastern United States from New Hampshire to Florida, west to Minnesota and eastern Texas, and in southern Quebec and Ontario Canada. There is also a disjunct area of occurrence in southern Mexico and Central America. It is common in eastern North America but uncommon in Minnesota, where it reaches the northwestern extent of its range. It is found in late summer and fall, alone, scattered, or close together but not clustered (gregarious), in deciduous and mixed forests. It grows on the ground under hardwood trees, especially oak, but also beech, aspen, and possibly maple. It has a mutually beneficial relationship (mycorrhizal) with the tiny rootlets of trees, absorbing sugars and amino acids while helping the tree absorb water.

As the common name and species epithet suggest, Variable-stalk Bolete is highly variable, in the size, in the cap color, and in the shape and surface texture of the stalk.

When it first appears, the cap is convex, dry, and covered with fine, velvety hairs. The color may be buff, tan, yellowish-brown, or grayish-brown. As it ages it becomes broadly convex to almost flat. Mature caps are 2½ to 8 (6 to 20 cm) in diameter and the upper surface is cracked or finely patched.

The stalk is mostly grayish-brown to dark brown, whitish just near the top and bottom. It is stout, often pot-bellied (bulbous), 3 to 6¼ (8 to 15 cm) long, and to 1 (1.0 to 3.5 cm) thick. It may be swollen in the middle, enlarged toward the base, narrowed at both ends, or more or less equal from top to bottom. The surface is usually prominently covered with a network of whitish or brownish ridges (reticulate), especially noticeable near the top. Sometimes the reticulation is reduced or fine.

When young, the pore surface is white, and the pores appear full. There are 1 or 2 pores per millimeter, and the pore tubes are to 1¼ (1 to 3 cm) deep. The pore surface becomes yellowish or olive with age.

The flesh of the cap and stem is white. It does not change color when bruised or cut. It is edible when young, but like other boletes, mature specimens are often riddled with maggots.

The spore print is olive-brown.

 
     
 

Similar Species

 
     
     
 
Habitat and Hosts
 
 

Mixed and deciduous forests

Oak and beech

 
     
 
Ecology
 
 

Season

 
 

Late summer and fall

 
     
 
Distribution
 
 

Distribution Map

 

Sources

4, 24, 26, 29, 30, 77.

 
  9/22/2022      
         
 

Occurrence

 
 

Uncommon in Minnesota

 
         
 
Taxonomy
 
  Kingdom Fungi (fungi)  
  Subkingdom Dikarya  
  Phylum Basidiomycota (club fungi)  
  Subphylum Agaricomycotina (jelly fungi, yeasts, and mushrooms)  
  Class Agaricomycetes (mushrooms, bracket fungi, puffballs, and allies)  
  Subclass Agaricomycetidae  
  Order Boletales (boletes and allies)  
  Suborder Boletineae  
 

Family

Boletaceae (boletes)  
  Subfamily Boletoideae  
 

Genus

Boletus (porcini and allies)  
       
 

Synonyms

 
 

 

 
       
 

Common Names

 
 

Variable-stalk Bolete

 

 

 

 

 

 

 

 

 

Glossary

Gregarious

In mushrooms, growing close together but not clustered.

 

Mycorrhizal

A symbiotic, usually beneficial relationship between a fungus and the tiny rootlets of a plant, usually a tree.

 

 

 

 

 
 
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AGShep

 
 

my backyard

 
    Variable-stalk Bolete   Variable-stalk Bolete  
           
    Variable-stalk Bolete      
           
 
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  AGShep
9/5/2022

Location: Isanti County

my backyard

Variable-stalk Bolete

 
           
 
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Created: 9/22/2022

Last Updated:

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