Undulata

Cryptocoryne undulata is a long-standing aquarium staple from Sri Lanka, a member of the same group as Cryptocoryne wendtii, and it behaves the way those plants are supposed to: it grows in unfertilised water, tolerates low light, and forgives neglect. Its leaves are brownish green with wavy, sometimes marbled edges, which is where the species name comes from, and a mature rosette reaches about 20 cm.

It was collected wild around Kandy in the central highlands, and in the tank it stays adaptable rather than picky. Water of 22 to 26 °C and a pH of 5 to 8 suits it, and it needs no CO₂, and fertilising with it is unnecessary. Stronger light and a nutrient-rich substrate make it grow faster and more compactly, while low light makes it taller and slower.

Propagation is simply cutting off the runners near the mother plant and replanting them. Its brown, undulating leaves earn it a place in the midground as a contrast to bright green and red plants, and it is best planted in small, spaced portions so each rosette has room.