The yellow-green alga Botridium
has clusters of small, saclike, coenocytic vesicles. Coenocytic
or siphonous organisms do not have cross walls separating individual
cells, creating tube-like thalli with many nuclei. The genus
grows on damp soil and has colorless rhizoids that attach underground.
The vesicles can be very large - as much as several millimeters
in diameter - and therefore can sometimes be seen without the
aid of a microscope. A thin peripheral layer of cytoplasm contains
the multiple nuclei and discoid plastids.
In
culture, Botridium cells often form irregular clumps.
When growing
in natural conditions, Botridium cells often develop colorless
rhizoids that allow them to attach to the substrate. These structures
may not
be present
while the genus grows in liquid culture medium, since the rhizoids
have no substrate
to attach onto and are unneccessary under these conditions.
