a small, usually flat, plant body not clearly differentiated into stems and leaves, formed by the germination of a spore.
Copyright: Mark Hyde, Bart Wursten, Petra Ballings and Meg Coates Palgrave, 2002-17
Hyde, M.A., Wursten, B.T., Ballings, P. & Coates Palgrave, M.
. Flora of Zimbabwe: Glossary details: prothallus.
http://www.zimbabweflora.co.zw/speciesdata/glossary-display.php?glossary_id=577, retrieved 24 March 2017