Pollen morphology of Sonchus and related genera, and a general discussion

The pollen morphology of the taxa belonging to the genera Aetheorhiza Cass., Launaea Cass., Reichardia Roth and Sonchus L. in the Iberian Peninsula has been studied with light and electron microscopy. The pollen is 3(-4)-zonocolporate and echinolophate (without polar lacunae, but in general with prelacunae), with equatorial ridges and 15—20 lacunae: 3—4 poral, 6—8 abporal and 6—8 paraporal. Small to medium size, P × E = 19—36 × 23—42 μm; sometimes two different sizes have been found. Exine 3—9 μm thick and ornamentation microreticulate and echinate. The results clearly show the relationships between genera.