Two new genera (Streptosarcina and Streptofilum) and three new species (Streptosarcina arenaria, S. costaricana and Streptofilum capillatum) of streptophyte algae were detected in cultures isolated from terrestrial habitats of Europe and Central America and described using an integrative approach. Additionally, a strain isolated from soil in North America was identified as Hormidiella parvula and proposed as an epitype of this species. The molecular phylogeny based on 18S rRNA and rbcL genes, secondary structure of ITS-2, as well as the morphology of vegetative and reproductive stages, cell ultrastructure, ecology and distribution of the investigated strains were assessed. The new genus Streptosarcina forms a sister lineage to the genus Hormidiella (Klebsormidiophyceae). Streptosarcina is characterized by packet-like (sarcinoid) and filamentous thalli with true branching and a cell organization typical for Klebsormidiophyceae. Streptofilum forms a separate lineage within Streptophyta. This genus represents an easily disintegrating filamentous alga which exhibits a cell coverage of unique structure: layers of submicroscopic scales of piliform shape covering the plasmalemma and exfoliate inside the mucilage envelope surrounding cells. The implications of the discovery of the new taxa for understanding evolutionary tendencies in the Streptophyta, a group of great evolutionary interest, are discussed.
The paper deals with first record of the representative of the nostocalean genus Stigonema in the terrestrial ecotope in the Forest-Steppe Zone of Ukraine. It was revealed in Cladonia dominated cryptogamic soil crust sampled from limestone outcrops with a rock-oak-hornbeam forest on the high bank of the Dniester Reservoir (Podilskyi Tovtry NNP). Heterocytous cyanobacterium with true branching identified as Stigonema minutum Hassal ex Bornet et Flahault formed prostrate blackish felty films on the surface of the crust. Information on morphological and dimensional features of the studied population, photomicrographs of natural material, characteristics of the habitat are given. Data on the distribution of the species within Ukraine, as well as ecological and biogeographic features of S. minutum are discussed.
The first record of a new for the flora of Ukraine species Myurella sibirica is reported. The species was found on the slope of Maslyatyn Mt. (at 381 m a.s.l.) in the Kremenets Mountains National Nature Park (Ternopil Region). It grew among other mosses on the soil layers in the cracks of vertical limestone wall, under the canopy of Betula klokovii near the forest meadow. Myurella sibirica is quite rare in the mountains of Europe and more common in mountains of Asia and North America. The species is listed in The IUCN Red List of Threatened Species (Vulnerable), Red Data Book of European Bryophytes (Endangered), European Red List of Mosses, Liverworts and Hornworts (Vulnerable) and several Red lists of European countries. Brief morphological characteristics, distinctions from other two species recorded in Ukraine (M. julacea and M. tenerrima), geographical distribution, ecological and coenotic peculiarities of the species, as well as original illustrations of the Ukrainian population are provided. Some issues on conservation of M. sibirica in Ukraine are discussed. The new record of M. sibirica is considered to represent a relict population.
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