Lineolae
Lineolae are areolae that are transapically elongated and are characteristic of Navicula sensu stricto, or Navicula in the Lineolate group.
Alternative Term
lineolate striae
Image Credit: Marina Potapova
The striae of Navicula capitatoradiata are lineolate, as are the striae of all the true Navicula.
Image Credit: Marina Potapova
Areolae are often aligned in rows to form striae. In the genus Navicula, the areolae are elongated in the apical direction forming lineolae, or lineolate striae. This image shows the lineolate striae of N. tripunctata in SEM.
Image Credit: Marina Potapova
The lineolate striae of Navicula species are visible in the light microscope in some species, but difficult, or not possible, to discern in others. Here, the lineolate striae of Navicula germainii can be seen.