Beiträge von Tori

Hallo,

da gibt es mehrere Hypoxylon-Arten in dem H.fuscum-Komplex, man kann sie nach Pigmente in KOH, Sporengrösse und Wirt unterscheiden. Ich habe ein provisorischer Schlüssel:

Schlüssel zu dem Hypoxylon fuscum-Komplex

Gemeinsame Merkmale: Sporen mit ablösbarem glattem Perispor, Keimspalte auf gewölbte Seite (oder nicht angegeben im Literatur), sigmoid (selten gerade) und fast sporenlang.

• 0a. Sporen (im Durchschnitt) kürzer als 12,5 µm ... 1
• 0b. Sporen länger ... 2
• 1a. KOH-Pigment violett (grau oder nicht vorhanden auf älteren Stromata), granules/Körnchen gelblich, auf Betulaceae (Betula, Alnus), Sp. 9,5–12,5 × 5–6 µm, X = 11 × 5,4 µm ... H. fuscoides J.Fourn. et al.
  • Diffuse Stromata auf nacktem Holz sind verwechselbar mit H. carneum Petsch (auf verschiedene Laubhölzer. Hat auch ablösbares Perispor, gelbliche granules, Sp. 8,8-11 × 4-4,8 µm, X = 9,8 × 4,6 µm, aber gerade Keimspalte inmitten eines dunkleren Bandes.)
• 1b. KOH-Pigment dunkelbraun, leicht oliv, granules zitronengelb, junge Stromata graubraun pruinose, auf Quercus (Europa), Sp. 11-13.5 × 4.5-5.4 µm, X = 11.6 × 4.8 µm .... H. porphyreum Granmo
• 1c. KOH-Pigment gelbbraun, oliv, hellbeige, granules pastellorange, orangebraun, auf Quercus (Iran), Betula und Carpinus (Europa), 9-12.5 × 4-6 µm .... H. eurasiaticum Pourmoghaddam et al.
• 2a. KOH-Pigment bernsteinfarben, oliv oder beige, granules orange, orangebraun, auf Alnus und Salix (Europa), Sp. 11–16 × 4,5–7,3 µm ... H. pseudofuscum Pourmoghaddam et al.
• 2b. KOH-Pigment bernstein- bis honigfarben, granules ??, auf Corylus (Europa), Sp. 12,5–15,8 × 4,8–7 µm .... H. fuscum (Pers.) Fr., sensu stricto

Literatur: pseudofuscum + eurasiaticum, fuscoides

Seltener vorkommen Funde von andere Hölzer, z.B. Prunus domestica, vielleicht werden sie eventuell auch eine eigene Name haben(?).

Tori

I had a lot of fun microscoping leaves, trying stains, polarisation etc. It begun when I needed to distinguish between Fraxinus excelsior and F. pennsylvanica on base of last year's skeletized leaves (Hymenoscyphus fraxineus + H. albidus grow on both species, but H. pusillus only on F. pennsylvanica). Fortunately, F. pennsylvanica is easily distinguished by the presence of large prismatic crystals along leaf veins. Here they are on a fresh leaf (native preparation, tangential section, polarised light), and on on old skeletized vein occupied by a Hymenoscyphus (piece of the vein squashed in KOH, polarized light):

Another task was to distinguish leaves of Prunus laurocerasus from Ilex aquifolium. The latter can be pretty variable, having all shapes from toothed to entire margin, which resemble the false laurel. Here is P. laurocerasus main vein in polarised light, slightly stained with cresyl blue:

Some trees can be distinguished not only by wood anatomy, but also by petiole anatomy - the vein bundles often have a genus-specific pattern. But this was the first time ever I looked into microscope and saw something smiling back at me (Sorbus aucuparia, water, in UV).

Hello,

this is not nectrioid, but Immotthia aff. atroseptata (Piroz.) M.E.Barr. Nice find!

Unlike I. atrograna or I. bambusae, original I. atroseptata has only light-colored spores and grows not on Hypoxylons, but on a discomycete Pestalopezia rhododendri (on Rhododendron leaves), so far it is only known from type collection. This one is its european double, which grows on Velutarina rufoolivacea, often very immature. All collections are from February to April, from Spain to Denmark (the first Czech record will be published next spring). Far as I know, no one did a DNA study yet. http://ascofrance.com/search_forum/713

Cheers,

Tori

Hello,

Öhrlinge look like the Otidea alutacea complex. Not very easy even with microscope.

Tori