11-08-2022 00:45
Stefan JakobssonOn a thin deciduous stick (Salix/Alnus/Betula) on
10-08-2022 18:45
François BartholomeeusenGood evening all, On 5 August 2022, a friend gave
11-08-2022 08:16
Josep Torres
Hola.Un muy diminuto Pirenomyceto sobre un tronco
06-08-2022 22:20
Marcus YeoI found this ascomycete today on dead leaves of Er
16-07-2022 17:01
Zetti MarioHi, I am doing some work with microfungi and durin
06-08-2022 20:43
Louis DENYAu bord d'un étang près de Belfort (alt 400m) su
07-08-2022 01:57
Stefan JakobssonA light-coloured Hymenoscyphus growing on a cone o
• Macro and habitat seems like Hymenoscyphus s.l.• Supported by paraphyses, spores and ascus rings.
• The spores, excipulum, and substrate make me think H. s.s.
• Possibly H. caudatus, based on spores, asci, and macro.
Habitat: On petioles and veins of dead leaves of Salix cf. caprea, possibly on a Betula cf. pendula leaf too (no micro), leaves well decayed, on the top of leaf litter, at the edge of a pond, mixed deciduous woodland, Low Weald, England, mid-September, after rain.
Apothecia: Whitish-yellowish, very small, diameter < 1 mm, short stipitate, receptacle whitish, disc opaquer and more yellowish, eventually plano-convex, margin uneven, relatively indistinct.
Asci: Mature and turgid ~110-125 x 8.5-10 um, cylindrical-clavate, 8-spored, biseriate when turgid, simple septa, rings bb, Hymenoscyphus-type, apex acute-truncate, thickening noticeable when flaccid, collar-like opening.
Spores: Scutuloid, quite variable, constricted in the middle, poles rounded, many smallish LBs in each half, most appearing to coalesce into 1-3 of medium size (in each half), uninucleate and aseptate.
Free spores in water: (13.8) 15.4 - 18.7 (19.3) × (4.2) 4.4 - 5.3 µm, Q = (2.7) 3.1 - 3.7 (4.4), n = 30, mean = 16.6 × 4.8 µm , Q mean = 3.5.
Paraphyses: Narrow cylindrical, ~2-4 um wide, multi-septate, rarely branching towards the apex, Hymenoscyphus-type VBs (apex with many medium-size, globose, dextrinoid VBs), pale yellow/chlorinaceous.
Medullary ex: Possibly textura porrecta (not tangled enough for intricata?), hyaline.
Ectal ex: Textura prismatica, hyaline.
Hymenium-0012.jpeg
Excipulum-0004.jpeg
I can imagine this is challenging as I found even distinguishing this species quite hard at first, and I noticed some variance in the spore measurements given. However, Declercq's unpublished key does seem to get me there, once I worked out it is in table 2 (low refractive VBs, usually not reddening, folicolous).
Declercq also describes var. constrictus, with small apos, spores with rounded bases, and no reddening with trauma, which seems to fit my observation. There are sequences available for several samples labelled as H. caudatus, do you know if these support heterogeneity or any subgroups?
There are some Chinese sequences under H. caudatus that seem to be related but not identical, but these are very far from my HB 7588c (KM114539) which matches by 0.2% MZ492984 Hymenoscyphus caudatus strain FeF217 from Poland and is a bit more distant to MZ492985 Hymenoscyphus caudatus strain FeF416.
Disturbing is a sequence that is 100% = FeF217, but uploaded as H. albidus:
JX976998 Hymenoscyphus albidus isolate Ha_10203_(VS) (Gherghel et al. 2012 unpubl., 2010 K.H. Rexer, Fraxinus exc.). Clearly this is far from true H. albidus.
The upload of 7588c was not done by me, it lacks collection data: Tübingen, on Fagus cupules. Spores are slghtly constricted, rather broad. A docu is in my caudatus folder.