Mycoheterotrophic Plants

How many of them are there?

Plantae Haitienses novae vel rariores IV. a cl. E. L. Ekman 1924-26 lectae

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