species, such as Cryptocoryne wendtii are said to be among the most versatile of aquarium plants); they tolerate low or bright light but grow faster in more intense light. This water plant's range is around 12 to 33 °C, and slightly alkaline to neutral pH. Plants of the genus Cryptocoryne, which range from India to New Guinea are found in very diverse conditions. Some are true acid loving plants such as C. pallidnerva, found in peat bogs in Borneo, while others such as C. crispatula var. balansae and C. pontiderifolia are found in streams with limestone beds—hard alkaline water. One species, C. ciliata is even found in semi-brackish water in some areas. It is one of the few aquarium plants that tolerates salt concentrations. Cryptocoryne plants have been in cultivation in the aquarium hobby since the late 18th century, although it was not until the 1960s that more than a handful of species was known and became more common in the hobby. New species still regularly crop up as interest in these plants widens and more collecting expeditions by private parties are carried out. Crypt melt A phenomenon often encountered when planting new crypts in an aquarium is commonly called Crypt melt, whereby the plant loses all its leaves. There seem to be two possible causes for this. Rapid environmental change is thought to trigger this, as these plants do not seem to adapt well to transplantion, and may need 30 days or so to become established and for the leaves to regrow. Experienced growers report that it is better to plant crypts in aquariums that have been established for at least three months. In the wild, crypts can grow fully submerged underwater, but in some plant nurseries they are often grown emersed and crypt melt could then be triggered by the change from emerse to submerse conditions. There is lately a trend for such nurseries to send crypts as just a rootstock (i.e. without the leaves) to reduce shipping costs and because the leaves will be lost anyway once planted in an aquarium. Other reports emphasise the need to change the aquarium water regularly to prevent the buildup of nitrates which are thought to trigger this condition (often referred to as a disease). Species Cryptocoryne affinis N.E.Br. in J.D.Hooker - Thailand, Malaysia Cryptocoryne alba de Wit - Sri Lanka Cryptocoryne albida R.Parker - southern China, eastern India, Bangladesh, Indochina