INTRODUCTION

Charophyta can be classified into 6 classes including Conjugatophyceae and Klebsormidiophyceae and there are about 4,738 species reported worldwide. There are about 4,346 and 44 species reported in classes Conjugatophyceae and Klebsormidiophyceae, respectively (Guiry and Guiry 2018). Domestically, there are 874 and 4 taxa of Conjugatophyceae and Klebsormidiophyceae reported, respectively (Lee and Kim 2015).

Desmids have been studied extensively by early microscopic researchers for its beauty of symmetrical form and structural diversity (Ralfs 1848). For this reason, more than 6,000 species of Desmidiaceae have been reported from different habitats around the world. In addition, external morphology, internal cell structure, systematics, sexual and asexual reproduction, and genetic studies were performed (Brook 1981).

The desmids are mostly attached algae distributed in acidic waters. Most of them are distributed in clean waters, but some occur in polluted waters. Also, there are aerial algae distributed in moist terrestrial ecosystems. Therefore, it plays an important role as a primary producer and in the secondary transition process (John et al. 2002). It has an important ecological position as an indicator of environmental change in aquatic ecosystem (Chung and Lee 1986).

And members of the filamentous green algae genus Klebsormidium are one of the essential components of soil crusts. These algae are widely distributed in terrestrial habitats worldwide (Hoffmann 1989).

For this study, we collected samples from fresh waters and aerial environments and added the unrecorded charophytes to the algal flora of Korea.

MATERIALS AND METHODS

From April 2017 to September 2017, freshwater and aerial charophytes were collected from Gangwon-do, Gyeongsangnam- do, Jeollanam-do, Jeollabuk-do and Jeju-do (Table 1). The collection was performed separately the planktonic and the periphytic algae. The planktonic algae were collected using a 20 μm-mesh phytoplankton net with a 30 cm diameter and a van Dorn water sampler. The periphytic algae was collected by scrubbing off aquatic plants, submerged land plants and rocks (Sournia 1978). Aerial algae attached to the bark of tree and the rocks were also collected. 1% Lugol solution was used for fixation.

The sample was identified with a light microscope (Axio Imager A2, Carl Zeiss, Germany / Olympus BX41, Olympus, Japan) at a magnification of 100 to 1,000. Photographs were taken using an AxioCam HRC camera (Carl Zeiss, Germany) and an Olympus UC-90 (Olympus, Japan). The unialgal samples were cultured in Bold’s basal medium (Bold 1949). The specimens were cultured under the following conditions: a temperature of 25℃, light/dark cycle of 16 : 8 and 40 μmol m^-2 s^-1 light (Stein 1973; Bold and Wynne 1978).

The taxonomic classification system was based on AlgaeBase (Guiry and Guiry 2018). The taxa were identified based on information taken from Prescott et al. (1977, 1981, 1982), Croasdale et al. (1983), Coesel and Meesters (2013) and Mikhailyuk et al. (2015).

RESULTS AND DISCUSSION

We identified six unrecorded taxa in Korea. The six taxa were Cosmarium quadrifarium f. octastichum, Euastrum turneri, Spondylosium nitens var. triangulare, Staurastrum kouwetsii, Staurodesmus dickiei var. latus and Klebsormidium subtile.

Cosmarium quadrifarium f. octastichum Nordstedt 1888 (Fig. 1)

Synonym:Cosmarium hexastichum var. octastichum Nordstedt 1873

Cells are above medium size, about 1.25 times longer than broad. The median constriction is deep. And sinus is narrowly linear. The semicells are semicircular, lower angles are subrectangular and a little rounded, lateral margin broadly convex over the apex. This form is distinguished from the typical by its semicells having 8 parallel series of emarginate warts in the marginal region, inner series often somewhat reduced and the facial protrusion with 7 or 8 vertical rows of granules. The length of cell is 47-48 μm, the width is 35-36 μm and the isthmus is 12 μm.

Ecology: This is a freshwater species (Guiry and Guiry 2018). We collected this species from the submerged plants in a large reservoir.

Distribution: North America: Tennessee (Johansen et al. 2007); South America: Argentina (Tell 1985); Australia and New Zealand: New South Wales (Day et al. 1995).

Site of collection: Sinpo-ri, Gangwon-do (September 14, 2017).

Specimen Locality: ACKU2017NR11

Genus Euastrum Ehrenberg ex Ralfs 1848

Euastrum turneri West 1892 (Fig. 2)

Cell is small and 1.5 times longer than broad. The semicell is truncate-pyramidal in outline. The basal angles are biundulate at the margins. The margins of semicells is retuse and converging to upper lateral lobules, a U-shaped sinus between the upper, lateral lobules and the polar lobe, which has a small protrusion below the apical angles where there is a short, stout spine. The apical margin is flat but unundulate, with an open median incision. The face of semicell has a median protrusion bearing a circle large granule, and cell wall with a scattering of granules in the apical lobules and over the face of the basal lobes. The lateral view is elliptic, the poles pointed with a mucro. The length of cell is 43 μm, the width is 30 μm and the isthmus is 7 μm.

Ecology: This is an epiphytic species and was collected from a swamp.

Distribution: Europe: Britain (John et al. 2011); North America: Northwest Territories (Sheath and Steinman 1982).

Site of collection: Bongsan-ri, Gyeongsangnam-do (June 8, 2017).

Specimen Locality: ACKU2017NR13

Genus Spondylosium Brébisson ex Kützing 1849

Spondylosium nitens var. triangulare W.B. Turner 1893 (Fig. 3)

Synonym:Leuronema nitens Wallich 1860

Cell is about as long as broad, sinus open and broadly rounded within. A variety has with the semicells 3-lobed, in vertical view triangular. The apices are evenly convex or truncately produced in the middle. The length of cell is 20- 25 μm, the width is 20-30 μm and the isthmus is 8-10 μm.

Ecology: This is an epiphytic species and was collected from a large reservoir.

Distribution: South-west Asia: India (Das and Keshri 2016); South-east Asia: Thailand (Hirano 1992); Australia and New Zealand: Northern Territory (Day et al. 1995).

Site of collection: Sinpo-ri, Gangwon-do (September 14, 2017).

Specimen Locality: ACKU2017NR14

Genus Staurastrum Meyen ex Ralfs 1848

Staurastrum kouwetsii Coesel 1996 (Fig. 4)

Cell is about as long as broad and deeply constricted. Sinus open from acute angled apex. Semicells are sub elliptic- rhomboid or sub pyramidal with broadly rounded angles, equally covered with rather stout spine arranged in concentric series around angles. Semicells in apical view are 3-angular with slightly concave sides and broadly rounded angles. The length of cell is 45-48 μm, the width is 37-41 μm and the isthmus is 12.5 μm.

Ecology: This species occurs in benthos and tychoplankton of oligo-mesotrophic, acidic water bodies (Coesel and Meesters 2013). We collected it from a stagnant small pond.

Distribution: Europe: Britain (Lang et al. 2014), Netherlands (Coesel 1997); North America: Virginia (Wołowski et al. 2011).

Site of collection: Seonheul-ri, Jeju-do (May 20, 2017).

Specimen Locality: ACKU2017NR15

Genus Staurodesmus Teiling 1948

Staurodesmus dickiei var. latus (Hirano) Lacoste de Díaz 1963 (Fig. 5)

Synonym:Staurastrum dickiei var. latum Hirano 1959

Cell is medium sized, about as broad as long and constriction is deep. Sinus is acute angled. This variety is different with relatively broader cells than the typical. Semicells are narrowly fusiform, the lateral spines are relatively long and downwardly directed. The length of cell is 27-30 μm, the width is 34.7-35.4 μm with spines and the isthmus is 6.5-8 μm.

Ecology: This type species occurs in benthos and plankton of acidic water bodies (Coesel and Meesters 2013). We collected it from a stagnant reservoir.

Distribution: Asia: Japan (Hirose et al. 1977); South America: Argentina (Tell 1985).

Site of collection: Yonggok-ri, Jeollanam-do (August 7, 2017).

Specimen Locality: ACKU2017NR16

Class Klebsormidiophyceae C. Hoek, D.G. Mann & H.M. Jahns 1995

Order Klebsormidiales K.D. Stewart & K.R. Mattox 1975

Family Klebsormidiaceae K.D. Stewart & K.R. Mattox 1975

Genus Klebsormidium P.C. Silva, Mattox & W.H. Blackwell 1972

Klebsormidium subtile (Kützing) Mikhailyuk, Glaser, Holzinger & Karsten 2015 (Fig. 6)

Synonym:Hormidium subtile (Kützing) Heering, Stichococcus subtilis (Kützing) Klercker 1896, Klebsormidium subtilissimum (Rabenhorst) P.C. Silva, K.R. Mattox & W.H. Blackwell 1972

Filaments are long and are composed of wide cylindrical cells. There is no depression between the cells. Chloroplast has 1 pyrenoid, which is located on the side of cell. The length of cell is 7-21 μm, the width is 6-8 μm.

Ecology: We collected this species from the bark of tree and rock. It lives at moist aerial environments.

Distribution: South-west Asia: India (Gupta 2012)

Site of collection: Busong-dong, Jeollabuk-do (April 8, 2017)

Specimen Locality: ACKU2017IA02