Pollen Morphology and Wall Stratification in Rubus L. (Rosaceae) in the Iberian Peninsula

A palynological study using LM and SEM was made of the morphology, ornamentation, apertural system and structure of the pollen wall, of the 18 species of the genus Rubus which are present in the Iberian Peninsula. We demonstrate: a) the stenopalynous character of the genus (isopolar, subprolate, 3-lobate, 3-zonocolporate and striate-perforate, except for R. genevierii whose ornamentation is striate-gemmate-perforate and with a striated margin); b) the lalongate shape of the endoaperture, due to the disappearance or thinning of the nexine; and c) the existence of two structural types, Type I granular and Type II columellar with clearly-defined columellar spaces or compact without intercolumellar spaces.