Glossary
Like the rest of this website, the glossary is a work in progress. If we’ve missed a term, please contact us to let us know the term and references.
Vola
A vola is an extension of silica from the side of an areola. A vola may be simple (e.g., Thalassiosira decipiens) or branched (e.g., Arachnoidiscus ehrenbergii). From Latin for the palm of the hand, based on the first described shape (Cox 2004 p. 36). Plural is volae. This structure is visible only with electron microscopy. Several volae combine to occlude an areola.
See also occlusion (a general term for covering).
Citations
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Publication Link: 10.11464/diatom1985.20.0_33
Image Credit: Marina Potapova
Image Credit: Mary Ann Tiffany
Image Credit: René van Wezel/Rijkswaterstaat, Creative Commons
Image Credit: René van Wezel/Rijkswaterstaat, Creative Commons
Image Credit: Marina Potapova
An areola of Aulacoseira crassipunctata with volae extending from its sides (SEM). Scale bar = 0.5 µm.
Image Credit: Mary Ann Tiffany
An areola of Arachnoidiscus ehrenbergii (SEM), occluded by a complex vola extending from its sides. Dark areas of the vola are openings to the cell interior. Scale bar = 1 µm.
Image Credit: René van Wezel/Rijkswaterstaat, Creative Commons
Center of valve face of Thalassiosira decipiens (SEM). Areolae have volae consisting of branches and bars. Scale bar = 1 µm.
Image Credit: René van Wezel/Rijkswaterstaat, Creative Commons
Internal view of Petroneis monilifera with areolae occluded by volae (SEM). In this genus, a cribrum is attached to the outside of each vola. Scale bar = 0.5 µm.