Pollen morphology in Lyperia (Scrophulariaceae) and related taxa with a multivariate analysis of the major patterns of pollen character variation in tribe Manuleae

Abstract

The pollen of all six species of Lyperia (Scrophulariaceae, tribe Manuleae) was investigated by light microscopy and scanning electron microscopy of whole and fractured grains. Pollen grains in Lyperia antirrhinoides (L.f.) Hilliard, Lyperia formosa Hilliard, Lyperia tenuiflora Benth., and Lyperia violacea (Jarosz) Benth. differed from those in Lyperia tristis (L.f.) Benth. and Lyperia lychnidea (L.) Druce in number and length of colpi, sculpturing of the colpus margin, reduction of apocolpial lumina size, reduction of exine thickness toward the colpi, ornamentation of the outer nexine surface, arrangement of columellae beneath the muri, direction of cross-sectional compression in elliptical muri, and relative dimensions of the muri and columellae. Pollen grains from 50 representative species of the putatively related genera Sutera and Jamesbrittenia were also examined. Correlations among quantitative pollen characters of tribe Manuleae and the Sutera complex were investigated by principal components analysis. Morphological similarities in the pollen of Lyperia, genera of the Sutera complex, and other Manuleae were summarized by ordination of the principal components data and (or) cluster analysis. The pollen grains of L. lychnidea and L. tristis differed from those of other Lyperia and stood apart from those of Jamesbrittenia, Sutera, and all other Manuleae. Pollen morphology in Sutera and Jamesbrittenia intergrades with that in tricolporate species of Lyperia.Key words: pollen morphology, Scrophulariaceae, Lyperia, Jamesbrittenia, Sutera.