In the 70s Mr. Schneider from Zugzen (CH) discovered a deviant specimen in an import shipment. It is a clear siamensis. The plant is described as C. cordata var. siamensis 'Rosanervig'.

Click on the picture to get the full image (ca. 50 kB)

Probably all plants in cultivation descend from the one (?) found by Mr Schneider in an import. The rosa veins however are not strong developed. Finding the right conditions in cultivation is difficult. cult. NJ3417 photo Jacobsen	The veins are pronounced but more yellowish. coll. unknown, cult B619	The spathe is rather short, the throat bright yellow, the margins of the limb of the spathe densely covered with red dots. cult. NJ3417 photo Jacobsen	Opened kettle of .Cryptocoryne cordata 'Rosanervig'. Nicely intermediate in characteristics. coll. unknown, cult B 619

The plant is easy to cultivate, both submerged in the aquarium as emerged. Unfortunately, the (mostly) rose veins may be less pronounced under some conditions, sometimes fully absent.

Updated January 2016

Literature: see the cordata group