This work is a contribution to the knowledge of Desmidiaceae biodiversity of Brazilian Northeastern region, poorly known in relation to its phycological flora. Collections were performed at eight sampling stations, following a transect on the longest lake axis during the rainy (April 1999) and dry (November 1999) seasons. The samples were concentrated in a 20 µm mesh net and preserved on 4% formalin solution. Analysis revealed that Desmidiaceae was the dominant group qualitatively. A total of 29 taxa were identified among the three genera, 18 belonging to Staurastrum, eight to Staurodesmus and three to Xanthidium. Excepting Staurastrum rotula, S. teliferum var. grönbladiiand Staurodesmus validus var. subvalidus, all species found represents new records to Maranhão State.
Biodiversity; Desmidiaceae; Zygnemaphyceae
