Estudios palinológicos de especies argentinas de los géneros Cereus, Cleistocactus, Denmoza, Echinopsis y Monvillea (Cactaceae, Cactoideae)

pollen grains morphology of nineteen species belonging to five genera (cereus, cleistocactus, denmoza, echinopsis and monvillea) of the subfamily cactoideae (cactaceae) in argentina, are described using optical and scanning electron microscopy: cereus aethiops haw., c. argentinensis britton & rose, c. forbesii otto ex c.f.f？rst., c. haenkeanus f.a.c. weber ex k. schum., c. stenogonus k. schum., c. uruguayanus r. kiesling; cleistocactus baumannii (lem.) lem., c. hyalacanthus (k. schum.) gosselin, c. smaragdiflorus (f.a.c. weber) britton & rose; denmoza rhodacantha (salm-dyck) britton & rose; echinopsis ancistrophora speg., e. aurea britton & rose, e. leucantha (gillies ex salm-dyck) walp., e. mamillosa gürke, e. oxygona (lynk) zucc., e. rhodotricha k. schum., e. tubiflora (pfeiff. & zucc.) and monvillea cavendischii (monv.) britton & rose, m. spegazzinii (f.a.c. weber) britton & rose. the pollen grains of the species analyzed are stenopalynous, mainly tricolpate, subspheroidal to prolate, tectum microperforate, equinulate, microechinate or nanoechinate. little differences in form and size were found. two pollen types could be established: pollen type cereus argentinensis and pollen type echinopsis mamillosa. a key to identify and distinguish the pollen types was given.