Series, or bundles, of rows of areolae oriented radially in some centric diatoms are termed fascicles.
Image Credit: Sarah Spaulding
Stephanodiscus niagarae is characterized by fasicles of 2-3.
Detail of S. niagarae, with the costae marked in red. The costae separate the 2-3 rows, or fascicles, of areolae.