a tube-like structure sometimes split
longitudinally for part or whole of the length with the two
margins overlapping, that encloses an organ either completely or
partially, e.g. a leaf-sheath of Poaceae.
Copyright: Mike Bingham, Annette Willemen, Bart Wursten, Petra Ballings and Mark Hyde, 2011-17
Bingham, M.G., Willemen, A., Wursten, B.T., Ballings, P. and Hyde, M.A.
. Flora of Zambia: Glossary details: sheath.
http://www.zambiaflora.com/speciesdata/glossary-display.php?glossary_id=674, retrieved 27 March 2017