On acetolysis resistant structures in the Orchidaceae— why fossil record of orchid pollen is so rare

Abstract
Orchidaceous pollen, grains occurring as monads, tetrads, massulae and compact pollinia were acetolysed. After acetolysis only the massulae can be allocated to the Orchidaceae. The internal structure of pollinia from higher orchids does not withstand the acetolysis, leaving unidentifiable remains. The meager fossil record is discussed in the light of these results.