Seventeen streams in 12 forest fragments were sampled during the dry season (June to August of 2007 and of 2008). Sixteen species belonging to 14 genera were found. Cyanophyta and Chlorophyta were the best represented algal division (44 and 38%, respectively), followed by Rhodophyta (12%) and Heterokontophyta (6%). Global species number was low, probably due to predominance of sand-clay substrates (65%) and of shaded stream segments (53%). Most species (69%) occurred in only one stream, a pattern often observed in lotic macroalgal communities. Vaucheria pseudogeminata was reported for the first time for Brazil, whereas Trichocoleus sociatus for this region. Comparing these macroalgal flora with those from other biomes of São Paulo State, the highest similarity was with Tropical Forest (56% in common), as expected because it is the nearest biome and also constituted by Semideciduous Seasonal Forest.
Diversity; macroalgae; Semidecidual Seasonal Forest; stream