Background and Aims:

Lobelia is the most diverse genus of Campanulaceae with 442 species; 86 occur in Mexico. The Lobelia macrocentron complex includes five endemic species to the country with restricted distribution. The pollen morphology of Lobelia is poorly known; therefore, the objective of the present work was to analyze and characterize the pollen morphology of Lobelia macrocentron and L. villaregalis in order to determine if there are diagnostic traits that allow then to be differentiated.

Methods:

Pollen grains obtained from flowers of herbarium specimens were acetolyzed following Erdtman’s technique, mounted on slides, and analyzed using a light microscope. In twenty pollen grains per species, nine morphological variables were measured: shape, polarity, polar axis and equatorial diameter in equatorial view, P/E ratio (polar axis/equatorial diameter), equatorial diameter in polar view, as well as the type, number and position of apertures.

Key results:

Lobelia macrocentron and L. villaregalis can be differentiated based on morphological characteristics of the pollen. The variables that differentiate them were the shape, size, and ornamentation of the pollen grains.

Conclusions:

Analysis of the pollen morphology of the studied species showed that the two species have exclusive characteristics so it can be a useful tool in the taxonomy of this group.

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