C. cf. griffithii 'Central Bintan Island'?

We found a slow moving water river with muddy base. If you looked carefully, you would discover that the entire bed of the river is covered with submersed cryptocorynes with brownish leaves covered with mud particles.  

The upperside of the leaves were brownish green in colour and the underside varied between reddish and greenish. No flower was found to confirm its identify. However, from the appearance of the leaves and from old records of cryptocorynes found at this location, we felt that it could maybe be comparable to C. griffithii?

The muddy substrate could be seen in the photograph below and the pH of the water was about 5.5.

Below is a short video clip taken at this location for your reference.