Conopeum

1. A flap of non-porous silica, often surrounding the external expression of the raphe system on the valve face creating a hyaline axial area.
2. An external siliceous covering slightly to distinctly elevated from the valve face; widths are variable, sometimes extending to the valve margin; visible with scanning electron microscope only. Found to contain nitrogen-fixing cyanobacteria in several taxa.
3. Sometimes also referred to as an axial band.
   

References

• Wehr, J.D. & Sheath, R.G. (Eds.) 2003. Freshwater Algae of North America: Ecology and Classification, Academic Press, San Diego, CA. 950 pp.

External Links

• Description of Sellaphora (at Craticula)