Plant ID

Looks like Truchoronis rivularis to me - Mexican Oak-leaf Plant - but the book I'm looking at (A Fishkeeper's Guide to Aquarium Plants by Barry James) doesn't say anything about red colouration. The description reads:
Height - up to 30cm
Characteristics - A herbaceous lant that produces trailing stems when grown emerse and upright stems when grown submerged. The thick stems bear opposite, light to dark green oval leaves with many indentations that give the laminae a toothed effect, hence the common name reference to oak leaves.
Aquarium use - As a middleground to background bunch plant. The attractively shaped leaves provide a refershing contrast to other foliage types. This newly introduced species grows well in aquarium conditions.
Propagation - Take cuttings or detach plants produced on runners.
Extremely adaptable.

HTH

Blinky hit it on the nail, but the plant was reclassified in 1970 as the monotypical species in the new genus Shinnersia. so now it is called Shinnersia rivularis.

it is a marsh plant that grows well submersed but will continue right up out of the water if given the chance. a reddish brown color is typical for the submersed leaves, being more pronounced in the new growth. likes alot of light though will grow with less and can grow like a weed in the tank with high light.