Two Arachnopezizas - Forum ASCOFrance

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Two Arachnopezizas

Gernot Friebes, 03-03-2014 19:08

Hi,

these two Arachnopezizas grew closely together on a soaked, strongly decayed stump. One species has whitish, very small apothecia. The other species is much more distinct, having bigger, bright orange apothecia.

The smaller one (photos of this collection are attached to this post) has 0- to 1-septate ascospores measuring 11-16.5 x 3.5-4 µm without appendages but I could observe a hyalin sheath around one ascospore. Asci have croziers, they are IKI bb, paraphyses are simple, without any remarkable content. The hairs are smooth and tapering towards the apex.

I haven't been able to find a matching species but that may also be due to the fact that I do not possess Korf's monograph: Korf, R.P. 1951 A monograph of the Arachnopezizae. – Lloydia 14: 129-180, so if anyone has a digital version I'd very much appreciate it!

PS: I should add that the macro photos are not mine.

scale = 10 µm

Gernot Friebes, 03-03-2014 19:14

Re : Two Arachnopezizas

Here's the second species. I think it may be A. trabinelloides since it fits very well the various images and descriptions I've seen of this species. However I'm not entirely sure yet how to differentiate between A. trabinelloides and A. cornuta so any advice is welcome. Ascospores measure 13.5-18(19) x 3.2-3.8 µm, they usually have a thin middle septum but can become 3-septate when overmature. Again no appendages observed. Paraphyes are somewhat irregular and filled with tiny yellow droplets. Asci are IKI bb. Hairs show an irregular outline and are incrusted by a yellowish substance. Upon adding IKI the hymenium shows a distinctive blue-green colour reaction.

Best wishes, Gernot

scale = 10 µm