Chicken Fat Mushroom

(Suillus americanus)

Conservation Status
Chicken Fat Mushroom
  IUCN Red List

not listed


not listed


not listed


Chicken Fat Mushroom is a widespread and very common “Slippery Jack” mushroom. It occurs in North America east of the Rocky Mountains. Isolated reports of it in the west might be misidentified specimens of Siberian Slippery Jack (Suillus sibiricus), a western species that grows under western white pine. Chicken Fat Mushroom is very common in the United States from the northeast to the Midwest, and in adjacent Canadian provinces. It is common Minnesota in the northeast, north-central, and metro regions. It is found from mid-July to mid-September in mixed and coniferous forests and anywhere else its host is found. It grows on the ground, usually in groups but not clustered, exclusively under eastern white pine. It obtains its nutrients from the rootlets of trees (mycorrhizal).

When young, the cap is bright yellow, convex, and slimy, and the margins are curled under. The cottony remnants of the partial veil are usually attached to the inside of the margin. As the mushroom matures the cap becomes broadly convex to flat, and sometimes has a small bump (umbo) in the middle. The mature cap is 1¼ to 4 in diameter, broadly convex, and sticky or slimy when moist. It frequently has reddish-brown scales, streaks, and/or patches, especially near the margin.

The stalk is slender, 1¼ to 4 long, to thick, and often crooked or bent. It is covered with reddish-brown glandular dots. On young specimens, the dots are not apparent because they the same color as the stalk. The stem usually does not show remnants of the veil because the veil hangs from the margin and does not touch the stalk.

There are no gills. The underside of the cap is a sponge-like pore surface. The pores are ¼ to deep and have angular sides. The pore surface is yellow at first, darkening with age, and bruising brown.

The flesh is thin and yellow. It is edible but the taste is not distinctive, and the cap becomes slimy when moistened. After removing the slimy skin and the spongy pore surface, there is little left to enjoy.

The spore print is cinnamon brown.


Similar Species

Habitat and Hosts

Mixed and deciduous forests. On the ground under eastern white pine.




Mid-July to mid-September


Distribution Map



4, 7, 24, 26, 29, 30, 77.




Widespread east of the Rocky Mountains. Common in Minnesota

  Kingdom Fungi (fungi)  
  Subkingdom Dikarya  
  Division Basidiomycota (club fungi)  
  Subdivision Agaricomycotina (jelly fungi, yeasts, and mushrooms)  
  Class Agaricomycetes (mushrooms, bracket fungi, puffballs, and allies)  
  Subclass Agaricomycetidae  
  Order Boletales (boletes and allies)  
  Suborder Suillineae  
  Family Suillaceae  
  Genus Suillus (slippery Jacks)  



Boletus americanus

Ixocomus americanus


Common Names


American Slippery Jack

American Slipperycap

Chicken Fat Mushroom

Chicken-fat Mushroom

White Pine Bolete




The common name of the genus Suillus is “Slippery Jack”. This refers to the slimy cap, a characteristic shared by most mushrooms in the genus. The single outlier in Minnesota is Painted Suillus (Suillus spraguei).










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


Partial veil

A protective covering over the gills or pores of a developing mushroom. At maturity it disappears, collapses into a ring around the stalk, or wears away into a cobwebby covering and ring zone.



A blunt or round protuberance on the end of the scale of some pine cones. It is the first year’s growth of a two year old scale.


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my backyard

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Young Mushroom

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    Chicken Fat Mushroom   Chicken Fat Mushroom  


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Suillus americanus - fungi kingdom
Nineli Lishina

Published on Jan 25, 2015

Suillus americanus - fungi kingdom




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Other Videos
  Suillus Mushroom (Suillus americanus?) Close-up
Carl Barrentine

Uploaded on Sep 11, 2010

Photographed at the Concordia Language Villages, Bemidji, Minnesota (08 September 2010). Go here to learn more about this mushroom:

  Chicken-fat mushroom / Suillus americanus

Published on Aug 24, 2014

This chicken-fat mushroom footage strikes me as extremely interesting. The colouration, textures, and morphology are all quite enigmatic. The fungus derives some of its nutrients through a mycorrhizal association with the roots of eastern white pine, receiving carbohydrates from the tree and providing it with minerals that the fungus' extensive mycelium (its "root" structure) collects. It also has pores instead of gills on its underside! They desiccate to beautiful black/brown/yellow hues in this footage.




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Location: Isanti County

my backyard

Chicken Fat Mushroom  




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