Mycoheterotrophic Plants - How many of them are there?

Mycoheterotrophic plant species (MHP, Leake 1994) lack chlorophyll and depend on their mycorrhizal fungus for carbon and nutrient supply. MHP were first counted by Johow (1889), who estimated 160 species of “achlorophyllous humus plants” in 43 genera and 5 families. Schmucker (1959) already counted 352 “holosaprophytic” species in 48 genera and 6 families. Furman and Trappe (1971) referred to “roughly 400 species”, 50 genera and 7 families. The most recent detailed review on MHPs (Leake 1994) lists 417 MHP species in 87 genera and 11 families. My own preliminary reassessment of Leake's list in 2008 resulted in 438 species/84 genera/10 families, but was just a rough estimate. Hence, we now want to set up a more reliable list of all mycoheterotrophic plants on earth, combined with additional informations such as synonymy, pictures and a bibliography. So far, the list of accepted species with taxonomic comments as well as synonyms (indicated in red font in the hierarchy on the left hand side) are complete except for Orchidaceae. The bibliography (more than 1000 references) collects the bibliographic data of the taxonomic literature mentioned up to now, as well as other articles dealing with all aspects of mycoheterotrophic plants. The citations in the taxonomic comments (pages) are hyperlinked with the bibliographic data.

The criterium to be included in this list is "optical achlorophylly" or at least nearly such. We are aware of intergrading dependences on the mycorrhizal fungus even in green plants (see the pages 'The case of "Pyrola aphylla", Obolaria and Bartonia or Stemona aphylla), as well as of different amounts of chlorophyll content, which often is even hidden by other colouring compounds.