Observation 163995: Irpex lacteus (Fr.) Fr.

Code: Bot_784/2014_DSC0038 and Bot_786/2014_DSC0132

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 desinitial 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.); 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.

Nikon D700/Nikkor Micro 105mm/f2.8 and Canon G11, 6.1-30mm/f2.8-4.5

Species Lists


Foto taken Febr. 23. 2014
Foto taken Febr. 27. 2014, four days after the previous picture.
Foto taken Febr. 27. 2014.
Sceletal hypha.

Proposed Names

57% (1)
Recognized by sight
Used references: (1) Personal communication with Mr. Bojam Rot, www.gobenabovskem.com
(2) A. Bernicchia, Polyporaceaes.l., Fungi Europaei, Vol. 10., Edizioni Candusso (2005), p 296. spores5-6.5(7)/2-2.5(3) basidia 15-25/3.5-5.5
(3) L. Ryvarden, R.L. Gilbertson, European Polypores, Fungiflora, Vol.1. (1993), p 352. spores 5-7/2-3 basidia 20-30/4-6
(4) G. J. Krieglsteiner (Hrsg.), Die Grosspilze Baden-Württembergs, Band 1, Ulmer (2000), p 329. 5-6/2-3
(5) J. Breitenbach, F. Kraenzlin, Eds., Fungi of Switzerland, Vol.2. Verlag Mykologia (1984), p 176. spores 5-6.5/2.2-2.8 basidia 20-25/3-4
(6) http://www.messiah.edu/...
Based on microscopic features:
Spores smooth. Dimensions: 5.1 [5.9 ; 6.2] 7.1 × 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 × 2.8 microns; Qe = 2.2. Basidia dimensions approximately 20 × 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.
Based on chemical features: 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.

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