This grass like crypt is the variant of Cryptocoryne crispatula with the narrowest leaves, which makes it particularly thrilling for aquascapers. Although it has been known for a long term it doesn't have the attention it merits in the hobby. It has green to reddish-brown smooth, clean or barely undulate leaves, 10-40 cm lengthy and only 2-4 mm wide. Under the water, the leaves possess stunning brown colorations. In trade, you'll regularly find the broader-leaved C. crispatula var. flaccidifolia to be sold under the name "Cryptocoryne tonkinensis".
