Not cleistanthum. Pedicels for G. cleistanthum are VERY short (0.5 mm, elongating to 1 mm when in fruit): plus flowers are downturned (these are erect). two flowers in lower right of photos appear to have 3-part calyx (I think: angle is bit awkward), which would make this G. elatinoides.
For convincing evidence for G. cleistanthum, look for the downturned fruits in the soil (see notes-discussion for 4241676). What was so special about 4241676 was that two Glossostigma species were growing in patches side by side: and making evident a strong visual difference in leaf between G. diandrum (4241677) and G. cleistanthum: and confirmed at herbarium.
Two flowers in lower right hand corner look like a 3-part calyx (tho its an awkward angle). If so, then its G. elatinoides.