Didymosphenia geminata is a nuisance freshwater alga, commonly referred to as "didymo". It is found in streams and rivers in much of North America. Didymo increasingly poses a threat to aquatic ecosystems because it forms extensive mats on stream beds. Decontaminating equipment between uses in different freshwater systems is important to prevent the spread of didymo.
Dr. Sarah Spaulding has provided this description for how to collect and report voucher material for Didymosphenia geminata. Report occurrences or suspected growths of didymo by collecting a small sample (put a pinch of the material in a vial with 90% ethanol or thoroughly dry material and fold inside a business card). Label samples with the date, latitude, longitude (provide detailed accurate site information). Note that the reports of samples can not be confirmed without a voucher specimen.
Send reports and samples to:
Dr. Sarah Spaulding
US Geological Survey, Fort Collins Science Center
1560 30th St.
Boulder CO 80309
Click here for a guide to field identification of didymo. Click here for more information on didymo.