Emex australis seeds (IMAGE) Cambridge University Press Caption Emex australis seeds have dimorphic morphology. Aerial seeds that form at the leaf axils along the stems (left) have radial symmetry and subterranean seeds that form on the lower section of the crown of the plant (right) have bilateral symmetry and shorter spines. Credit Photo by Dr. Catherine Borger Usage Restrictions N/A License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.