Exine structure in Dasyphyllum brasiliense (Spreng.) Cabrera (Barnadesioideae - Asteraceae): aspects of development for identifying the cavea
Keywords:
development, sporoderm, exine, pollen grain, taxonomyAbstract
Based on observations under light microscopy, the pollen grains in Dasyphyllum brasiliense (Spreng.) Cabrera were found to be tricolporate, with intercolpar depressions, a thick exine, microechinate and caveae. The cavea is identifi ed when the ektexine pulls away from the footlayer, which depends on the pollen grain’s stage of development or its degree of hydration, both related to changes in volume. Among the four species of Dasyphyllum that occur in Rio Grande do Sul, only D. brasiliense has caveae.
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