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 ha s been studied with light and electron microscopy. The pollen is 3(-4)-zono colporate and echinolophate (without polar lacunae, but in general with pre lacunae), with equatorial ridges and 15-20 lacunae: 3-4 poral, 6-8 abporal and 6-8 paraporal. Small to medium size, P x E = 19 - 36 x 23-42 mu m; some times two different sizes have been found. Exine 3-9 mu m thick and ornamen tation microreticulate and echinate. The results clearly show the relations hips between genera.