Milk-white Toothed Polypore

(Irpex lacteus)

Conservation Status
Milk-white Toothed Polypore
  IUCN Red List

not listed

     
  NatureServe

not listed

     
  Minnesota

not listed

     
           
           
           
 
Description
 
 

Milk-white Toothed Polypore is widespread in Europe and North America. It is very common in the eastern United States to the Midwest, including Minnesota, but rare in the Southwest. It grows flat (resupinate) on the bottom and sides of logs and fallen branches of hardwood trees, infrequently also on conifers. It usually obtains its nutrients from dead wood (saprobic), possibly also from live cherry wood (parasitic). It is exceptionally resistant to pollution toxicity.

The fruiting body is a patch of pore surface spread out flat (effused) on a branch or log (substrate). It is dry, stiff, and white, off-white, or cream-colored. Adjacent patches often fuse together creating a long row. There are 2 or 3 pores every thirty-second of an inch (1 mm). The pore walls are thin and disintegrate unevenly. As the walls break down the spore surface becomes maze-like. Eventually, only flattened, tooth-like projections less than ¼ (6 mm) long remain. When growing on the side of a log or branch it may develop shelf-like caps. If present, the cap is to 1½ wide, whitish to grayish, often concentrically zoned, and densely covered with velvety hairs. There is no stem. The flesh is thin and tough. It is not edible.

 
     
 

Similar Species

 
     
     
 
Habitat and Hosts
 
 

Dead hardwood logs and branches

 
     
 
Ecology
 
 

Season

 
 

Annual but persists year-round

 
     
 
Distribution
 
 

Distribution Map

 

Sources

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

 
  7-5-2019      
         
 

Occurrence

 
 

Widespread and very common

 
         
 
Taxonomy
 
  Kingdom Fungi (fungi)  
  Subkingdom Dikarya  
  Division Basidiomycota (club fungi)  
  Subdivision Agaricomycotina (jelly fungi, yeasts, and mushrooms)  
  Class Agaricomycetes (mushroom-forming fungi)  
  Subclass Agaricomycetidae  
  Order Polyporales (shelf fungi)  
  Family Irpicaceae  
  Genus Irpex  
       
 

There is wide disagreement about the family to which the genus Irpex belongs. NCBI places it in Irpicaceae, Fungi Growing on Wood (Gary Emberger, Messiah College) in Phanerochaetaceae, Encyclopedia of life in Polyporaceae, MushroomExpert in Steccherinaceae, and until 2019, Index Fungiforum placed it in Meruliaceae. Index Fungiforum very recently transferred Irpex to the family Irpicaceae.

 
       
 

Synonyms

 
 

Boletus cinerascens

Boletus tulipiferae

Coriolus lacteus

Coriolus tulipiferae

Daedalea diabolica

Hirschioporus lacteus

Hydnum lacteum

Irpex bresadolae

Irpex diabolicus

Irpex hirsutus

Irpex lacteus

Irpex pallescens

Irpex sinuosus

Irpiciporus lacteus

Irpiciporus tulipiferae

Microporus chartaceus

Microporus cinerascens

Polyporus chartaceus

Polyporus tulipiferae

Polystictus bresadolae

Polystictus chartaceus

Polystictus cinerascens

Polystictus cinerescens

Polystictus tulipiferae

Poria cincinnati

Poria tulipiferae

Sistotrema lacteum

Steccherinum lacteum

Trametes lactea

Xylodon bresadolae

Xylodon hirsutus

Xylodon lacteus

Xylodon pallescens

Xylodon sinuosus

 
       
 

Common Names

 
 

Milk-white Toothed Polypore

 
       

 

 

 

 

 

Glossary

Resupinate

In fungi: referring to the fruiting body lying flat on the surface of the substrate, without a stalk or a cap.

 

Saprobic

Obtaining nutrients from non-living organic matter, such as decaying plant or animal matter.

       
Visitor Photos
   

Share your photo of this fungus.

This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Attach one or more photos and, if you like, a caption.

       
Luciearl
       
  Milk-white Toothed Polypore   Milk-white Toothed Polypore
       
  Milk-white Toothed Polypore   Milk-white Toothed Polypore
       
  Milk-white Toothed Polypore   Milk-white Toothed Polypore
       
  Milk-white Toothed Polypore   Milk-white Toothed Polypore
       
MinnesotaSeasons.com Photos
   
  Milk-white Toothed Polypore   Milk-white Toothed Polypore
       
  Milk-white Toothed Polypore   Milk-white Toothed Polypore
       
  Milk-white Toothed Polypore   Milk-white Toothed Polypore
       
  Milk-white Toothed Polypore    
       
       

 

Camera

     
Slideshows
   
  Milk-white Toothed Polypore (Irpex lacteus)
Bill Keim
 
  Milk-white Toothed Polypore (Irpex lacteus)  
     
  Irpex lacteus
Amadej Trnkoczy
 
  Irpex lacteus  
 
About

Album description

Irpex lacteus (Fr.; Fr.) Fr. Elench. Fung. p145, 1828, syn.: Sistotrema lacteum Fr.
Milk-white toothed polypore, DE: Milchweisser Eggenpilz
Slo.: belkasti rašpovec

Dat.: Feb. 23. 2014
Lat.: 46.35947 Long.: 13.70424
Code: Bot_784/2014_DSC0038
File names: from Irpex-lacteus_raw_1.xxx to Irpex-lacteus_raw_8.xxx.

and

Dat.: Feb. 27. 2014
Lat.: 46.35947 Long.: 13.70424
Code: Bot_786/2014_DSC0132
File names: from Irpex-lacteus_raw_10.xxx to Irpex-lacteus_raw_11.xxx.

Habitat: alpine valley, an opening in mixed forest with predominantly Fagus sylvatica followed by Picea abies; modestly inclined southeast oriented mountain slope, overgrown calcareous ground composed of scree, rocks and boulders; mostly in shade, partly protected from direct rain by tree canopies; average precipitations ~ 3.000 mm/year, average temperature 7-9 deg C, elevation 560 m (1.950 feet), alpine phytogeographical region.

Substratum: cut down trunk of Fagus sylvatica lying on ground, in its late initial phase of integration; the trunk was massively infected also with Trametes hirsutum.

Place: Lower Trenta valley, between villages Soča and Trenta, right bank of river Soča, near 'Na melu' place, East Julian Alps, Posočje, Slovenia EC.

Comments: fruit body mostly resupinated but also effused-reflexed; very large, about 1.5 m x 20 cm, about 2-3 mm thick, context thinner than pore layer; small 'pilei' up to 8(12) mm off the substrate; hymenophore with initially distinctly irregular angular, almost labyrinthine pores soon becomes irpiciform to hydnoid (compare Figs. 8. and 10.); smell indistinctive, taste initially indistinctive, after some time slightly unpleasant; 5% KOH reaction on context and pore layer mild, color changed to somewhat darker ocher-beige; SP abundant, white-yellowish with a slight green tint, oac014. No hypha clamps have been observed. All observed traits fit well to expectations for Irpex lacteus except cystidia. The fact that I haven't found conspicuously encrusted cystidia puzzles me.

Spores smooth. Dimensions: 5.1 [5.9 ; 6.2] 7.1 x 2.5 [2.8 ; 2.9] 3.2 microns, Q = 1.9 [2.1 ; 2.2] 2.4; N = 47; C = 95%; Me = 6.1 x 2.8 microns; Qe = 2.2. Basidia dimensions approximately 20 x 4.5 microns.Olympus CH20, NEA 100x/1.25, magnification 1.000 x, oil, in water (spores) and NEA 40x/0.65, magnification 400x, in water, congo red (hymenium, cystidia). AmScope MA500 digital camera.

Herbarium: Mycotheca and lichen herbarium (LJU-Li) of Slovenian Forestry Institute, Večna pot 2, Ljubljana, Index Herbariorum LJF

Ref.:
(1) Personal communication with Mr. Bojam Rot, www.gobenabovskem.com
(2) A. Bernicchia, Polyporaceaes.l., Fungi Europaei, Vol. 10., Edizioni Candusso (2005), p 296.
(3) L. Ryvarden, R.L. Gilbertson, European Polypores, Fungiflora, Vol.1. (1993), p 352.
(4) G. J. Krieglsteiner (Hrsg.), Die Grosspilze Baden-Württembergs, Band 1, Ulmer (2000), p 329. (5) J. Breitenbach, F. Kraenzlin, Eds., Fungi of Switzerland, Vol.2. Verlag Mykologia (1984), p 176.
(6) http://www.messiah.edu/Oakes//fungi_on_wood/poroid%20fungi/species%20pages/Irpex%20lacteus.htm

 
     

 

slideshow

       
 
Visitor Videos
 
       
 

Share your video of this fungus.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Attach a video, a YouTube link, or a cloud storage link.
 
 

 

 
     
     
       
       
       
 
Other Videos
 
     
     
     
       

 

Camcorder

 
 
Visitor Sightings
 
           
 

Report a sighting of this fungus.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Be sure to include a location.
 
  Luciearl
10/9/2018

Location: Cass County

Milk-white Toothed Polypore

 
           
           
 
MinnesotaSeasons.com Sightings
 
   

 

 

Binoculars


Created: 10/15/2019

Last Updated:

About Us | Privacy Policy | Contact Us | © 2021 MinnesotaSeasons.com. All rights reserved.