In the 1950's Shirley Aquatics in England imported a large Cryptocoryne from Kalimantan, in Indonesian Borneo under the (now invalid) name "Cryptocoryne grandis" We know there were exportations of a giant red form of cordata from Kalimatan around 1950.
In 2010 T.S. Wang explored the Central Borneo region for Cryptocoryne and found plants in two locations that appear similar to the plant sold as "C. grandis" so many years ago.
This is the larger of the two, found growing submersed in Dayu, Kalimantan, in Central Borneo and in river made deeper by recent flooding during the rainy season but despite the depth of the rover the leaves grow up to the surface and then hang under it and still trail a bit, they is, they're longer than the river is deep. One leaf spans a mans hand and them some, Wang noted this was one of the larger Crypts he'd ever seen.