Riccardia graeffei

Riccardia graeffei (Graeffe's Riccardia) is a liverwort species with a wide distribution in tropical Asia, Australia and the Pacific Islands. It colonises moist sites, e.g. soil and rotting wood in secondary forests.¹ R. graeffei is described as extremely variable, but a thin border along the thallus margin, one cell layer thick and 3-5 cells wide, is typical of the species.¹

According to Kasselmann (2010), the Riccardia cultivated as an aquarium moss was collected in the 1990s by Holger Windeløv at the Namtok Ton Sai waterfall on the island of Phuket (Thailand) and identified as Riccardia graeffei by the moss expert Benito C. Tan (University of Singapore).²

The name R. graeffei is often used in the aquarium plant trade, but at least three different Riccardia types are in cultivation, and without microscopic examination it is impossible to say which of them is R. graeffei. Moreover, there are very many Riccardia species worldwide, and identification is very difficult and, without information on the natural origin, probably impossible in many cases. Aquarium Riccardia is also often labelled Riccardia chamedryfolia in the trade, but according to Kasselmann (2010) this species is probably not in cultivation.

For Riccardia species as aquarium mosses see Riccardia spp.