Pollen dimorphism in threeTeucrium species (Lamiaceae)

In the Iberian Peninsula and Balearic Islands pollen dimorphism was found inTeucrium fruticans L.,T. pseudochamaepitys L., andT. rotundifolium Schreber. Generally, this dimorphism shows two sizes of pollen grains, the smaller more or less collapsed. The percentage of pollen viability is calculated. Differences in size between viable and nonviable pollen grains are similar, being about 40% inT. fruticans andT. pseudochamaepitys, and about 26% inT. rotundifolium. With regard to pollen viability, the percentage of male sterility is higher inT. fruticans, in which from male sterile (ms) plants, 100% nonviable pollen was obtained from every flower observed. InT. pseudochamaepitys andT. rotundifolium with rare exceptions, the percentage of nonviable pollen does not seem to be significant.