The genus Jaagichlorella Reisigl (Trebouxiophyceae, Chlorophyta) and its close relatives: an evolutionary puzzle Author Darienko, Tatyana University of Göttingen, Albrecht-von-Haller-Institute of Plant Sciences, Experimental Phycology and Sammlung für Algenkulturen, D- 37073 Göttingen, Germany & M. G. Kholodny Institute of Botany, National Academy Science of Ukraine, Kyiv 01601, Ukraine Author Pröschold, Thomas University of Innsbruck, Research Department for Limnology, A- 5310 Mondsee, Austria text Phytotaxa 2019 2019-01-14 388 1 47 68 http://dx.doi.org/10.11646/phytotaxa.388.1.2 journal article 10.11646/phytotaxa.388.1.2 1179-3163 13725500 Jaagichlorella roystonensis var. epilithica Darienko & Pröschold var. nov. ( Fig. 5A–H ) Description: Young cells are spherical or sometimes irregular with relative thick cell wall, 6.4–7.3 μm in size. Chloroplast by young cells saucer-shaped, covers a little bit more than a half of the cell; with a single pyrenoid surrounded by many starch grains. Mature vegetative cells are spherical 9.1–10.0 μm, sometimes 11.8 μm in diameter, with cup-shaped chloroplast, sometimes slightly removed from the cell wall in the bottom part of the cell and occupied the middle position of the cell; chloroplast relatively thick, green or yellowish-green. Cells with numerous, colorless vacuoles. Old cells are spherical, 10.9–13.6 μm in size, sometimes up to 17,3 μm, with reduced small chloroplast, cells contain several vacuoles and fill around 1/3 of the cell. Reproduction is by 2-4-8 unequal autospores. Autosporangia are spherical or very often irregular, (8.2)–9.1–10.0 μm, sometimes they can reach 16.4–20.9 μm. Large autospores 6.4–7.3 μm, (up to 10.0 μm), small autospores 3.7–5.4 μm in size. SSU and ITS rDNA sequences (GenBank: MH780940) and ITS-2 Barcode BC-3a in Fig. 3 . Type locality: Lithophytic on rocks in Germany . Holotype (designated here): The authentic strain SAG 2133 is cryopreserved in a metabolic inactive state at the Culture Collection of Algae ( SAG ), University of Göttingen , Germany . Iconotype (designated here to support the holotype ): Fig. 5C in this study. Etymology : The epithet of this variety indicates its epilithic life style. Comment: Differs from the type variety by ecology and differences in the variable regions of SSU and ITS rDNA sequences.