A very small species, the largest mature cap was about 1.5cm across. Looks very much like a Laccaria in some stages of development.
Spores 5 – 5.5 × 9 – 10 micrometers.
Regarding the host tree, Etelvina Gándara says “It is a Betulaceae, I do not sure if is Alnus (I saw fruits on the soil) Ostry or Carpinus… you could ask to Claudia Gallardo, she is expert in cloud forest trees”
Claudia says that it isn’t possible to determine the tree genus by the photos alone, but since we saw cones it is Alnus.
Herbarium specimen in the Cortinarius 2012 bag.