The fifteen species of Coleochaetales have gained attention recently because they are implicated as the closest living relatives of the Plantae. Some species have parenchymatous growth, nurturing of the zygotes, and a fossil record of an appropriate age, all of which strengthen the implication. In addition, they are easily found and studied. We have found them, quite accidentally, attached to the leaves of freshly collected aquatic flowering plants while observing them under the microscope.
For more on the Coleochaetales, you can try the Protist Image Data Base for information about the genus Coleochaete.
You can also search the World Data Center Algal Database for culture collections of Coleochaete and Chaetosphaeridium.