UK Fungi

I collected this unusual Ramalina from an elm branch on the Pensthorpe Estate, TF9528, VC28 West Norfolk, in October of last year. It was growing alongside typical though not abundantly fertile R. fastigiata. Judging by ascospores -- which are colourless, 1-septate, mainly curved or reniform, and around 12 x 5 µm in size -- it seems also to be R. fastigiata, despite not looking very much like its neighbour.

I'd be grateful for a confirmation or correction, as it seems an unusual specimen (to me at least) in a number of ways:

• The lobes are very narrow, mostly less than 3mm wide

• The lobes branched copiously, but in short tufts, giving the thallus a spiky or furry appearance

• At the end of the short tufted branches are globular or granular structures like blastidia, which rub off fairly easily

• Only one apothecium, or possibly two (I couldn't find the possible second one again after losing sight of it)

• K+ red medulla -- though this isn't impossible for R. fastigiata -- but otherwise C- and Pd-

At first, I thought the 'blastidia' at the tips of the lobe tufts might be minute soralia, and the lichen might be a candidate for R. pollinaria or R. europaea. Indeed, so far as it's possible to tell from the scan, it looks somewhat like specimen H-ACH 1831C in the Acharius herbarium in Finland, which Gasparyan et al (2017) assign to R. pollinaria sens. str.

• H-ACH 1831C scan: https://laji.fi/en/view?uri=http:%2F%2F ... A.H9502933

• Gasparyan et al. (2017) on R. pollinaria and R. europaea: https://www.cambridge.org/core/journals ... 257B561CC7

But as mentioned above, the lobe-tip structures seem not to be soralia. They seem rather to be corticated, even if fragile. Moreover, Gasparyan et al.'s concept of R. pollinaria sens. str. doesn't include any lichens found fertile, and their concept of R. europaea involves straight rather than curved ascospores.

Again, the 'best fit' seems to be R. fastigiata. LGBI3 indicates that R. fastigiata in 'moist sites' the species is rarely fertile, and also that 'very narrow, straggling morphs' can occur, with 'numerous angled branches giving the thallus a spiny appearance'. Does this specimen fit that description, or am I missing something obvious?

Photos and micrographs below.