The two recognised British Olpidiums are O. radicale and O. brassicae although both may end up being complexes. Doweld transferring them to Olpidiaster and Leiolpidium is not fully accepted as it was not backed up by molecular evidence. Both are still Olpidiums in the handbook of microfungal parasites (https://www.aber.ac.uk/waxcap/downloads … _Aug24.pdf). However Olpidium radicale is missing from the UKSI. I have added it to the BMS list and will forward it to the UKSI shortly. A second however is that neither of your host species is listed in the handbook. As Arthur Chater is probably the expert in this group, I will contact him about these host species.

Arthur says that they have a number of records of O. radicale on Cochlearia and Tripleurospermum maritimum so radicale it is and it will soon be on the UKSI.