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25-04-2025 22:48

Gustaf Fredell Gustaf Fredell

Hello,I hope everything is going well. I couple mo

18-04-2025 23:16

Robin Pétermann Robin Pétermann

Bonjour, Voici une probable Mollisia, genre que j

24-04-2025 21:35

Thorben Hülsewig

Hi there,last week i could found this asco on an S

25-04-2025 17:24

Stefan Blaser

Hi everybody, This collection was collected by J

25-04-2025 09:33

Josep Torres Josep Torres

Ascomata shaped like deformed black grains, measur

24-04-2025 21:53

Lothar Krieglsteiner Lothar Krieglsteiner

... 15.7.24 in the Alps. There were many asci with

23-04-2025 20:16

Miguel Ãngel Ribes Miguel Ángel Ribes

Good afternoon Looking for Octospores / Lamprospo

24-04-2025 15:03

Henri Koskinen

Hello, I collected this Lasiobolus 22.04. near Hel

23-04-2025 19:58

Francois Guay Francois Guay

I found this interesting Orbilia sp. one year ago

22-04-2025 10:37

François Bartholomeeusen

Also found on April 18, 2025 on an old seed-pod of

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Epichloe sp with hyperparasite
B Shelbourne, 16-08-2024 14:16
B ShelbourneI found the (asco)stroma of an Epichloe sp. a few days ago in southern England, and there are also signs of a green-spored hyperparasite that could be Bionectria epichloe.

It has been very interesting to learn about the genus Epichloe, and I would appreciate any feedback on identifying the species.

I can't confidently identify the host grass, but my best guess is genus Poa and then E. typhina (s.l.), the latter may fit the macro, and asci and spore sizes. Although I did find some shorter spores that I thought could be part spores, but I'm not convinced now. Next time, I think capturing ejected spores would be helpful.

The habitat is an open chalk hill (downland) with several grasses and small plants around, 128m altitude, at a junction of paths, surrounded by semi-natural grasslands, and agricultural, horse, and hay fields, in the South Downs.

*Host

I have no experience with vegetative characters of grasses, and I thought it may be Agrostis stolonifera, but after more reading and looking at the plant then my best guess is Poa cf. pratensis.

A low grass, with bluish, tapering leaves, shiny on the underside, folded in the stem, the sheaths have a rough texture (especially on the main stem), many have turned purple with age, the ligules are white, membranous, broadly acute, several measured 1-4 mm, no apicules identified, all parts appear hairless, the base of the main stem is almost white with some old brown sheaths, the lateral roots are small and there are no rhizomes.

*Epichloe

Macro: Stroma covering most of an internode and part of the flag leaf on the living main stem of a grass, ~20 x 2-3 mm, signs of necrosis in the top part and further development of the stem and inflorescence is arrested. Underneath is a dense white mycelium with a smooth, spongy appearance, on the outside yellowish-organish with immersed perithecia (fertilised), ~0.2-0.3 mm diameter, approximately several thousand, gelatinous texture and appearance, densely arranged, orange, globose-pyriform shape, ellipsoid from above.

Perithecia with pyriform shape, neck extending towards the surface,  neck protruding from stroma, inner margin and neck strong pigmented, with many long and slender asci developing from the base, no paraphyses (as expected), many small yellowish globose vacuoles in surrounding hyphae.

Asci narrow-cylindrical, sometimes appearing to bulge in the middle, ~150-180 x 8-10 um, shorter asci possibly immature, and probably slight underestimate for mature asci, apex hemispherical, highly refractive, inamyloid, poroid, apparently dark unrefractive cap developing in maturity, appears easily separated from ascus, bases with croziers.

Spores: Hyaline, multiseptated, with many small to tiny greenish vacuoles, usual reaction from contents when cells die, two shapes apparently associated
- filiform, ~(110) 140-170 (180) x 1-2 um, several counted with 6-9 septa,
- some ~45-80 um long, apparently less septa but hard for me to see.
Not confident that these are part spores, but not sure if immature or what the explanation might be.

In the lower layers textura globosa with small yellowish vacuoles, possibly the stroma.

*Hyperparasite

Macro comparable to Bionectria epichloe, no micro currently.

On the surface of the stroma are patches of white mycelium, some appearing to have green conidia developing at the centre (e.g. photo 9), some signs of the mycelium invading the stroma, and also suppression and necrosis (e.g. photo 6).
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