Collected recently in Vermont in the Green Mountains.  I believe this is Hysterium hyalinum.  It is on a decorticated hardwood branch (along with Berkleasmium conglobatum and a Patellarioid asco which I posted earlier.)  Long naviculate hysterothecia with an apical slit.  They are mostly flattened at the apex.  The longest of them are 2-2.5mm long and slightly less than .5mm wide.

Spores are hyaline at first and eventually brown. Mostly 3 septate, constricted at the sepatations.  20-25 x 7.5-9µm. 

Asci are 92-110 x 15-17µm. 

This seemed to key out to H. hyalinum using Boehm's key and matched fairly well with information from Marion Lohman, "A Cultural and Taxonomic Study of Hysterium hyalinum".