Probably Isopterygiopsis pulchella as suggested by Bryony Macmillan.
However, I have only glanced at this specimen. It is not Catagonium. File as Isopterygiopsis pulchella as per Bryonly Macmillan's notes.
Other identifications
Identification
Determined name:
Catagonium nitens
Determiner:
B. H. Macmillan
Identification date:
1993-11-16 (Verbatim: 16 Nov. 1993)
Preferred name:
Catagonium nitens (Brid.) Cardot
Active:
no
Identification type:
Determination
Note:
I believe this to be the flagelliferous form of Catagonium nitens referred to by Sainsbury (1955 p. 455). When the cushion is dissected distichous branches are present. Interestingly the stems have axillary rhizoids with papillose walls as described by Iwatsuki (1987) for Isopterygiopsis pulchella (Hedw.) Iwats.