Cryptocoryne cordata var. siamensis 'Rosanervig'

This plant is a "white-variegated" cultivar of Cryptocoryne cordata var. siamensis. The leaf midrib and longitudinal veins are coloured white to light pink, while the rest of the leaf surface is green. This Cryptocoryne was first found in 1972 by Peter Schneider (Zuzgen, Switzerland) among imported aquatic plants and propagated further. Josef Bogner and Niels Jacobsen presented the plant in the magazine Aqua Planta (No. 2 / 1985) as cultivar 'Rosanervig' of C. cordata. For a long time the exact origin of this variegated-leaved Cryptocoryne was unknown, until Claudia Hary found a corresponding plant among other forms of C. cordata var. siamensis at a natural site in Southern Thailand approx. 50 kilometres south of the city of Krabi.¹

The leaf shape in C. cordata var. siamensis 'Rosanervig' is oblong-ovate to broadly lanceolate, as in the form long known as "Cryptocoryne blassii" of var. siamensis.

The cause of the white to pink leaf marking of this Cryptocoryne is not yet known. A mutation is suspected, but also a virus infection. The marking is developed to varying degrees depending on growing conditions, and it has long been discussed which factors are decisive here.

- To be continued -