Identification: On Alnus leaf veins, small bean shapes

Greetings,

I am posting this at request of a friend on Saltspring Island BC Canada who found these small bean shapes attached to the leaf veins of Alnus rubra.

It has been posted on a few sites for ID, without success.

Any ideas would be appreciated.

Thanks!

[EDIT: Sorry just noticed that only one photo uploaded originally, now the rest are attached]

 

In case helpful, a few comments from Vail's posts; "almost pure white inside and hardish throughout." "Salt Spring Island on red alder leaves on the ground at about 250m."

EDIT: Ideas put forward so far include fungi, slime mould and insect gall. Another person on Vancouver Island reported also finding these on alder leaves, in quantity recently.

All ideas welcome :-)

 

Aceria spp?

A. nalepai maybe.

Or Eriophyes laevis?

 

Mystery solved in another group! It turns out these are sclerotia of fungus (Macro)Typhyla phacorrhiza! Vancouver's Paul Kroeger grew these from sclerotia stage to ID from some specimens found in Queen Elizabeth Park!