The aperture may have a lid (operculum), hence is described as operculate. However the term inaperturate covers a wide range of morphological types, such as functionally inaperturate (cryptoaperturate) and omniaperturate. Inaperaturate pollen grains often have thin walls, which facilitates pollen tube germination at any position. Terms such as uniaperturate and triaperturate refer to the number of apertures present (one and three respectively). Spiraperturate refers to one or more apertures being spirally shaped.
tHe aperTUre mAy HavE a Lid (OpercULuM), hence iS desCribed as OpErcUlaTE. However the teRm inaPertUrAte cOveRs a Wide rangE of mORPHologIcal TyPes, suCh as fUncTIOnAlLy iNaPerturatE (CryPTOAPErturAtE) aNd oMniaperturate. INaperaTuRATe pollen grAiNS OFten HAve thin waLls, whicH fAcIlitates PolLen TubE germInation At any pOsition. tERmS such as unIaPERTURatE and triApertuRaTe ReFER to thE nuMBEr Of aPeRtUrEs present (OnE and thrEe ResPeCtivelY). spIrapErturate refers tO one or morE AperTurES beINg spiRALlY shApEd.