The genus Petroderma never been reported from the coast of Korea. In this study, our collection from Chaeseokang is matched with P. maculiforme morphologically. Petroderma maculiforme is characterized by having small irregular light to dark brown crusts, a basal layer of irregularly shaped cells giving rise to erect parallel filaments which easily separate with pressure, single chromatophore per cell, small spherical to cylindrical unilocular sporangia in a terminal position, and plurilocular sporangia narrower than erect filaments or wider and shorter than erect filaments in a terminal position. In addition, Hineksia sordida was also collected from Korea. It is mostly epiphytic and characterized by uniseriate filamentous thalli forming loose tangled masses, sparse and spiral branching, some long lateral branches, rhizoids occurring throughout the plant, plurilocular and unilocular sporangia scattered on separate plants. Our molecular analyses based on the rbcL gene reveal that our samples of P. maculiforme and H. sordida are nested within the clades of Petroderma and Hincksia, respectively. Therefore P. maculiforme and H. sordida are reported as new records from Korea based on morphological and molecular analyses.

Ralfsia longicellularis is known as an endemic species in Far East Asia. In this study, we report R. longicellularis as a new record from Korea based on morphological and molecular analyses. Molecular analyses based on plastid-encoded rbcL gene sequences and morpho-anatomical studies were undertaken on Ralfsia species, a poorly studied genus from Korea. Ralfsia longicellularis is mainly characterized by a dark brown thallus; 770-1200 μm thick, curved cells in the creeping and ascending parts of the filaments; basal layer and erect filament cells with a width-to-length ratio of 1 : 1.5 to 10; narrowshaped sporangia on-stalk cells at the base of the paraphyses; and mostly uniseriate plurilocular reproductive organs capped with 1-2 sterile cells. The R. longicellularis samples from Korea in this study were similar to ones collected from the type locality (Peter the Great Bay, Russia) in morphology. The rbcL analyses also revealed that our Korean R. longicellularis samples were placed in the same clade with Russian materials, within a Ralfsia clade but distinct from the congeners.

Acinetospora filamentosa and Microspongium stilophorae are reported as new records from South Korea based on morphological and molecular analyses. A. filamentosa is mainly characterized by having the sparsely branched erect filaments, the scattered meristematic zones, forming crampons, plurilocular sporangia on both prostrate filaments and lower part of erect filaments, and spherical to oval unilocular sporangia formed either sessile or with a pedicel. M. stilophorae is an epiphytic thalli mostly on Stilophora sp. It is characterized by prostrate filaments with irregular cells, short erect filaments with short ramuli, phaeophycean hairs, uniseriate plurilocular sporangia on the terminal part of erect filament. Our molecular analyses of rbcL and cox1 genes reveals that A. filamentosa and M. stilophorae are nested within the clades of Acinetospora and Microspongium, respectively.

Feldmannia chitonicola is reported as a new record from Korea based on morphological studies in laboratory-cultured materials and molecular analyses. F. chitonicola is mainly characterized by a small size (1-2 mm), erect filaments mostly unbranched, plurilocular sporangia produced on both prostrate and laterally on the basal part of erect filaments, and 2 types (lanceolate and ovate) of sporangia. In our cultures, sporangia production was slower at 10°C than in 16°C and 20°C. Our molecular analyses of rbcL and cox1 genes supported its independence from other congeners reported for Korea. This is the first report of F. chitonicola for western Pacific.

Acinetospora asiatica and Botrytella reinboldii are reported as two new records from S. Korea based on morphological studies and molecular analyses. A. asiatica is mainly characterized by the presence of sparsely branched uniseriate filaments with diffused meristematic zones, the formation of crampons at right angles, and the formation of plurilocular sporangia on both prostrate and erect filaments. B. reinboldii is characterized by the presence of irregularly alternating branched uniseriate filaments attached by rhizoids, and single or clustered plurilocular sporangia with a single opening. Molecular analyses of rbcL gene revealed that A. asiatica and B. reinboldii are placed within each clade of Acinetospora and Botrytella, respectively.