Peter Döbbeler has used this method extensively to study the bryophilous fungi of specific host plants preserved in herbaria. While it has the disadvantage that several characters of living collections are lost, it allows for the screening of huge numbers of host plants from large geographic ranges, giving us an understanding of frequency and biogeography.
Permission must be obtained for so-called “destructive analysis” as bryophilous fungi cannot be identified without some damage to the collection. Infected host fragments need to be removed, occasionally stained, and examined using high power microscopy. All specimen preparation work needs to be done under a dissecting microscope, preferably one with variable magnification options from 20X – 45X as higher magnification is sometimes required to spot smaller fungal fruitbodies.
In 2019, I screened over 200 vouchers labelled as Ulota bruchii from the British Bryological Society’s collection housed at the National Museum of Wales, thanks to correspondence with Katherine Slade. This was initiated after the discovery of two interesting, tiny fungi on Ulota bruchii during a 2018 field trip to Kindrogan Field Centre in Scotland. I re-found both fungi during the herbarium screening, one only once and the other twice. It later became apparent that both were cryptic “micro-lichens”: a Porina sp. and an undescribed species of Normandina.
During a BBS field trip in 2021 to Merioneth in Wales, I came across a fungus with rather large, blackish discoid apothecia on Gymnomitrion obtusum and G. crenulatum. Examination of the material when I returned home showed distinctive ascospores resembling those of Stenocybe nitida, but smaller. I then searched my herbarium for Gymnomitrion, finding a sample of G. crenulatum I collected on the Isle of Arran in July 2018. The same fungus appeared to be present largely buried within the shoots, with a small number of emergent mature apothecia. Peter Döbbeler directed my attention to poorly known Dactylospora and Lecidea species found on Gymnomitrion. I aim to use a combined approach of herbarium specimen examination and targeted searches of living material to better understand this and similar fungi.
Bryophilous fungi 