Morphology, distribution and ecology of the freshwater red algae Paralemanea (Batrachospermaceae, Batrachospermales, Rhodophyta) in Serbia

This paper describes the morphology, distribution and ecology of 15 populations of Paralemanea collected from 2004 to 2011 in 12 rivers in Serbia. On the basis of morphological and reproductive characteristics, two species were identified: P. annulata (12 populations) and P. catenata (3 populations). Morphological (presence of a stalk, thalli length, nodal diameter (ND), internodal diameter (ID), node and internode diameter ratio (ND:ID) and reproductive (arrangement of spermatangial sori, length and diameter of carpospores, presence of Chantransia stage) features described in the literature are generally confirmed in the populations from Serbia. True branching was observed in six populations of P. annulata in the gametophyte stage. False branching (whorled branching) occurred in five populations of both species observed. In the Pcinja (P2), Ibar (IB5) and Crnovrska rivers (CR10), the number of whorled branching was 6-11 (P. annulata). For P. catenata the number of such branching was 3-5 in the Nisava River (N8) and Sokobanjska Moravica River (SM12). False branching appears at damaged thalli, somewhat repairing it. Algae belonging to the Paralemanea genus were found at altitudes from 160 to 780 m (P. annulata), and from 240 to 400 m (P. catenata), at water temperatures ranging from 11.5 to 29?C (P. annulata) and from 12.6 to 17.4?C (P. catenata), in neutral and weakly alkaline waters, with a high level of oxygen concentration, with conductivity ranging from 70 to 433 ?S/cm for P. annulata, and 260 to 440 ?S /cm for P. catenata. It was also observed that P. annulata and P. catenata often grow in oligotrophic conditions and rarely in eutrophic conditions.