Mycoheterotrophic Plants

How many of them are there?

Thismia Griffith

The largest genus in Thismiaceae, Thismia (an anagram of the name fo plant anatomist Thomas Smith) coined by Griffith (1844, 1845), has numerous synonyms, which have been established, rejected and reactivated by several botanists over the last 150 years. This is in part due to its pantropical and rarely even extratropical distribution, but also to the quite variable shapes of its corolla structures. However, most contemporary taxonomist consider the genus as an entity, aside to Afrothismia, Oxygyne, Haplothismia and Tiputinia, but categorize the species in subgenera and sections, which take up some of the generic names of the past. Common features are the urceolate and caducous corolla tube above the inferior ovary, the six stamens combined with an annulus close to the throat of the corolla tube and bend downwards into the tube with their short filaments, thus leaving some space between them and the style with stigmas. The six tepals, however, as well as the details of the stamens and interstaminal lobes, are very variable in shape and ornamentation. Schlechter (1921), who provided a first worldwide synopsis of the Thismieae (today Thismiaceae), argued in favor of a narrow circumscription of Thismia comprising only the australasian species with free tepals and adnate anthers. He seperated those species having the inner tepals fused above the corolla tube (appearing like a miter) as Sarcosiphon (including the Bagnisia and Geomitra) or Scaphiophora (erect structure emerging from the mitra). In general, Schlechter splitted the 'Thismieae' in many genera according to specific tepal and staminal shapes, namely Thismia, Sarcosiphon, Scaphiophora, Glaziocharis, Myostoma, Triurocodon, Triscyphus, and Ophiomeris, along with the still valid Oxygyne and Afrothismia. However, although Jonker (1938) still kept some of the genera and even reactivated Geomitra of Beccari (1877), the fusion of all these generic taxa in Thismia is widely accepted (Maas et al. 1986, Maas-van de Kamer 1998, Merckx et al. 2006), although Govaerts et al. 2007 keeps the genera Geomitra and Scaphiophora (see page on Thismia appendiculata).

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith