This is a transverse serial sections through the seed cone of recent Pinus pinea, from the base of the cone to its apex, showing the presence of three spirals and their clockwise arrangement starting at ca. 17 s (out of a total of 35 s). This video can also be viewed from the Botanical Society of America’s YouTube channel at http://youtu.be/05JfmXRRCDg.
Credit: Video by Carole T. Gee. From Gee, C. T. 2013. Applying microCT and 3D visualization to Jurassic silicified conifer seed cones: A virtual advantage over thin-sectioning. Applications in Plant Sciences 1(11): 1300039. doi:10.3732/apps.1300039.