Pollen morphology of alpine butterworts (Pinguicula L., Lentibulariaceae)

Abstract The pollen morphology of Pinguicula alpina , P. arvetii , P. grandiflora subsp. grandiflora , P. grandiflora subsp. rosea , P. hirtiflora , P. leptoceras , P. poldinii , P. reichenbachiana , and P. vulgaris , belonging to the Alpine flora, was studied. The pollen grains, coming from different populations, were investigated using light microscopy and scanning electron microscopy. The pollen size, the shape (P/E ratio), the number of colpori and the exine ornamentation are, for Pinguicula , important diagnostic characters. Pinguicula pollen grains are medium sized (∼ 30 μm), trinucleate, isopolar, radially symmetric. The shape of the grains is variable from oblate spheroidal to prolate spheroidal and they are (4)–5–9–(10)-zonocolporate. The prevalent ornamentation is rugulate–microreticulate, P. alpina has a rugulate–reticulate ornamentation and only P. hirtiflora has a perforate ornamentation. A pollen key, based on micromorphological data, is presented.