Species of the genus Oedogonium in streams in the northwest region of Sao Paulo State, Brazil

Abstract

In the northwest region of the Sao Paulo State, the genus Oedogonium (Oedogoniaceae, Chlorophyta) is very common and abundant in lotic environments. In running waters, where specimens usually occur only in vegetative state, almost the totality of the populations cannot be identified in infrageneric level, because the specific taxonomy it is based on the reproductive structures. With the purpose of detailing the taxonomic knowledge on this group, collections of Oedogonium populations were carried out from May/2004 to September/2005 in two streams, totaling 47 samples. All the specimens were collected in vegetative phase and, during 25 to 68 days, were maintained in closed flasks filled with tap water in illuminated place to induce the reproduction and some populations became fertile allowing the identification in specific level. Six species were identified and O. globosum Nordstedt f. nanyohense Jao and O. vaucherii (Le Clerc) A. Braun ex Hirn var. vaucherii. vaucherii are cited for the first time to Brazil, while O. capilliforme var. capilliforme Kutzing f. lorentzii (Magnus & Wille) Hirn, O. crassum (Hassall) Wittrock ex Hirn var. subtumidum Hirn f. amplum (Magnus & Wille) Hirn, O. hirnii Gutwinski ex Hirn and O. varians Wittrock & Lundell ex Hirn var. varians are firstly recorded occurring in this region.