Cibaomyces: 1 sp. Europe & East Asia.
(Hymenopellis: 4 spp left. Presumably belong in Oudemansiella. India(?), USA, …?)
(Dactylosporina: 1 sp left. Presumably belongs in Oudemansiella. East Asia. The other 5 spp are in Oudemansiella: Europe, Central & South America.)
Oudemansiella: 55+ species. Worldwide.
Paraxerula: 4 spp. Europe, East Asia, USA.
(Ponticulomyces: 2 spp. Both belong in Oudemansiella. East Asia.)
Xerula: 7-12 spp. Worldwide.
MO said this genus (Xerula sensu lato) was in Marasmiaceae because there are several (incorrect) MO Name Descriptions which put Xerula in Marasmiaceae.
When MO shows a Name, it wants to show a Classification. MO first sees if there’s a Description, including a Classification, for that Name. If so, it uses that information. If not, it looks elsewhere.
For Xerula sensu lato, MO looked for another Description (for another name) which said where the genus Xerula belongs. MO found such Descriptions and picked one (at random).
1 The names with those Descriptions are:
I haven’t corrected them, but anyone is welcome to do so. Perhaps the best practice is to include only one higher level of classification; if even higher levels are reclassified, there’s only one place that needs changing. (The downside is that it will take more clicks to get to even higher levels.)
It’s in Physalacriaceae.