a thickened, raised mass of hardened
- (in Poaceae) a hard projection at the base of the floret or spikelet the sharp point of the seed;
- (in Orchidaceae) the raised structures, often consisting of ridges,
papillae or projections, occurring on the upper surface of the
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: callus.
http://www.zimbabweflora.co.zw/speciesdata/glossary-display.php?glossary_id=95, retrieved 23 March 2017