Hallo Malcom,
try Saccobolus saccoboloides because the spore-clusters are very loose and the ascospores free at maturity.
Jacky

Thanks Jacky
I did look at that in van Brummelen and it is the only one mentioned with the spore separation feature. The asci is the right size and shape and although the spores are a bit on the small size
I cannot see anything else it could be and unlike a previous suggested find on the forum many of the spores are definitely separating.
Mal

Hello Malcolm,

To me your determination seems to be correct.
I do have some samples of my own collection from 2013 on rabbit dung.
Ascus 117.9-35.3 um expanding in length before cluster release in this case to 130 um with almost the same width.
Spore cluister 47.8-52.0x14.7-15.7 um. 
Spores 19.3-20.5x8.2-10.0 um, spores are blunt at both ends, covered with fine warts.
Paraphyses 1,7 um with 2.7 um at the top.

Before pressure is given to the deck glass clusters are still compact i.a.w. pattern 1 (fig-1) but with a litte pressure they separate inside the ascus (fig 2) at first in two pairs of 4 spores and scattered soon after that.

It seems that clusters stick together when they are surrounded by a gelatinous envelope and scatter without one.
Van Brummelen did not state that the cluster of S. citrinus has an envelope and I did not see one.

Thanks Joop for the agreement.
Mal