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Cryptocoryne undulata

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Family: Araceae, Subfamily Aroideae

Common Name:

Origin and Habitat: Endemic to Central Sri Lanka. Grows submersed in streams and rivers and emersed along the banks.

Ideal position in aquarium

Mid-ground to fore-ground; in small tanks (5 gallon or under) it may be used as background.

Lighting requirements

Low to moderate.

Growth rate


Minimum Tank Suggestion


Water parameters

Soft to medium hard (< 15 dGH), acidic to basic (pH 6 to 7.5) water, optimum temperature 22-26C/71-80F.


The lanceolate crinkled leaves of this species may be chocolate brown, olive green, or reddish-brown on the upper-side and a rosy copper on the underside. A height of six inches makes this a beautiful contrasting plant in the fore- to mid-ground of the aquarium.

Unlike other species in the genus where the leaves grow tightly from a rosette, C. undulata has a small internodium [space between leaf nodes] between each leaf. There is a triploid form with wider leaves than the original species, but it is difficult to identify since its appearance is very close to both C. beckettii and C. walkeri.

Daughter plants are produced from the rhizome, and when these have a few leaves and roots the rhizome can be cut apart and the daughter plant separated; or the daughter plants can be left to form a clump with the parent.

This is another relatively easy plant to grow in any substrate, but the best growth and leaf colour will occur in one that is enriched (soil, a plant substrate, or with substrate fertilizer).

This species has a confused taxonomic history. It was described twice, in 1909 and 1920, and eventually this plant was known as C. willisii (Baum)--until it was determined that the name should rightly be applied to what was then C. nevillii. The description by Albert Wendt (1955) of C. undulata was selected. Rataj's name C. axelrodii is a synonym (invalid). The species epithet undulata refers to the undulate or wavy edges of the leaves.

Crypt Melt: All species in the Cryptocoryne genus require stable water parameters/conditions and light, and once planted, crypts should not be moved. It generally takes up to 30 days for a crypt to become established. Within a couple of days of any significant change in temperature, pH, hardness, light intensity or duration, nutrient availability or disturbance to the roots by moving (either within the aquarium or to a different aquarium), the plant may "melt." This condition involves the leaves disintegrating into a pile of mush, sometimes within a day or two. The roots usually remain alive, and if not disturbed (siphon away the "mush" but do not disturb the roots) new leaves tend to appear within a matter of a few days or sometimes longer, even up to several weeks or (more rarely) months. Some authorities report that introducing plants to an established aquarium (3+ months) can reduce the occurrence of a melt.

Cryptocoryne naturally occur in tropical parts of SE Asia from India to New Guinea; most species occur in a relatively small area. They grow in slow-flowing streams and rivers, along the banks of faster streams, and in marshes and flooded forest; they are adapted to growing emersed and submersed according to the seasonal floods. All crypts have a fairly thick rhizome from which the leaves arise in a rosette. They generally propagate vegetatively by runners in the substrate. Flowers are produced but only when grown emersed (during the "dry" season in nature).

Crypts are quite specific with respect to light and water parameters. The species on Sri Lanka prefer slightly acidic to slightly basic pH and medium hard to hard water, while those native to Borneo and the Malay Peninsula that occur in blackwaters prefer very acidic and soft water. The latter also grow in shaded areas exclusively, while occasionally those from Sri Lanka are found in sunny locations as well as shade. While some species may have quite specific requirements, in general most crypts can be cultivated in soft to medium hard, acidic to very slightly basic water, in a substrate of sand and gravel to which fertilizer may be added. Moderate light is recommended for optimum growth. Any significant or sometimes even minimal changes to water, substrate or light will cause some species to melt as described above.

The Cryptocoryne genus was erected by Friedrich Ernst Ludwig von Fischer in 1828. The name derives from the Greek crypto (hidden) and koryne (club), a reference to the "kettle," the spadix enclosed by the spathe. The genus Cryptocoryne along with the very closely-related genus Lagenandra [these plants are native to India and Sri Lanka] comprise the Cryptocoryneae tribe within the Aroideae subfamily of the Araceae family. The classification of this genus is complicated and not all botanists are in agreement. Usually the flower must be studied to accurately identify a species since leaf forms can vary due to differing aquarium conditions. There are now over 60 species in the genus (Robert Paul Hudson), and several have numerous synonyms which add to the confusion of identification.


Kasselmann, Christel (2003), Aquarium Plants [English edition].

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