From 2006 to 2010, Takashige Idei investigated the Mekong river for Cryptocoryne in Thailand, Laos and Cambodia. The results are very impressive. In Aqua Planta 35(4) two new plants are presented. More articles will come in the future.
Cryptocoryne mekongensis differs from all others by having a typical pronounced collar and a rough limb of the spathe with transverse rims. The habitat is the same as for C. crispatula var. decus-mekongensis, at some places they grow together, also with var. crispatula.
Click on the picture to get the full image (ca 50 k)
Cultivation of C. mekongensis is easy in loamy sand with or without some peat litter, but it may take an extra year to flower it. In July the plant starts withering, all the leaves will go down in this resting phase and a few spike like leaves develop (in nature it will be submerged). Only in September / October it will thrive again normal leaves. Because of its seasonal character it is not suited for the aquarium.
Updated July 2012
Idei, T., J.D. Bastmeijer & N. Jacobsen, 2010. Geschichten vom Mekong: Zwei neue Cryptocorynen (Araceae). Aqua-Planta 35(4): 139-146 (see the Document service, included an English translation)
Mekong River Commission (for water heights and predictions) at: http://ffw.mrcmekong.org/