Some microalga species may accumulate extracellular polysaccharides,
such as a gelatinous mass that encloses its cells, and is known as
envelopes, sheaths or capsules. These structures are very common among
the Desmidiales. However, studies concerning their functions, properties
and structures are still incipient. Spondylosium panduriforme is a
filamentous desmids, enclosed by a great and continuous capsule with
well-defined borders firmly bond to the cell. These characteristics can
be observed through light microscopy in Indian ink preparations. The S.
panduriforme capsule is taken as an essential part of the cell, and
points out the importance of this structure for its proper functioning
[1,2].