• ALGAE
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• v.20 no.1
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• pp.37-42
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• 2005

The morhology and life history of Stylonema cornu-cervi Reinsch from Japan were investigated. The species had multiseriate erect thalli from a basal cell. The thalli usually branched dichotomously, occasionally trichotomously near the base, and non-branched thalli were sometimes observed. A dichotomous branch on the upper portion near the base occurred only one time on each erect branch. Cells contained a stellate chloroplast, which was composed of a central rounded part with an obscure pyrenoid and 5-8 cup-like lobes connected to the central part by a small thin stipe. The biseriate part was observed on the six-celled stage in culture, and the grown thalli were multiseriate except for base and apices. Monospores forming from the immediate transformation of vegetative cells were observed. Thalli grew at 15-25$^{\circ}C$ and died at 10 and 30$^{\circ}C$. The fastest growth and maturation were observed under 25$^{\circ}C$ and 14L:10D. Although S. alsidii (Zanardini) Drew usually had uniseriate thalli, irregularly branched multiseriate thalli had been reported in cultures. It is possible that in the previous report the thalli were confused with S. cornu-cervi. In this report, S. cornu-cervi were distinguished from S. alsidii in that the branches were few, the multiseriate portions were observed on the early stage (six-celled stage), and the grown thalli were multiseriate except at the base and apices.

• Fisheries and Aquatic Sciences
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• v.20 no.10
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• pp.25.1-25.5
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• 2017

An economic marine alga, which is considered to be an important source of carrageenan, was collected from Jindo of the southern coast of Korea. This species shares the vegetative and female reproductive features of Ahnfeltiopsis and is characterized mostly by its small size (up to 8 cm), terete to subterete thalli at the lower portion, cartilaginous in texture, dichotomous branches, rarely produced proliferations, and an absence of hypha-like filaments in the medulla. It is distinguished from other Korean species within the genus by the thallus feature. In a phylogenetic tree based on the molecular data, this alga nests in the same clade with A. concinna from Japan but forms a sister clade to A. concinna from Mexico and Hawaii (type locality). However, the genetic distance among those sequences was calculated as 0.1-1.3% for rbcL and 1.1% for COI sequences, considered to be intraspecific variation within the genus. Based on the morphology and molecular analysis, this alga is identified as A. concinna originally described from Hawaii. This is the first record of the species in the Korean marine algal flora.

• ALGAE
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• v.25 no.4
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• pp.187-195
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• 2010

The genus Rosenvingea is well known in the tropics. Four species have been reported from Pacific Mexico: R. floridana, R. antillarum, R. intricata and R. sanctae-crucis. We collected a plant (Boca del Cielo, Chiapas) that we identified as Rosenvingea orientalis, a species not previously reported from Pacific Mexico. We were able to characterize the life cycle of this species for the first time in laboratory culture. It reproduced exclusively by plurilocular sporangia (plurangia). The mature plants were up to 6 cm long with cylindrical to compressed fronds (to 2 mm wide) with dichotomous branches in the upper half of the thallus. The medulla was hollow with 2-3 layers of large inflated colourless cells at the periphery. The cortex was comprised of 1 layer of small cells, each with a single chloroplast and pyrenoid. Linear plurangial sori with phaeophycean hairs formed along the mature fronds. Zoospore germlings developed into prostrate filamentous systems, each with a single phaeophycean hair that gave rise to a single erect shoot with multiple hairs arising near the tip. Molecular phylogeny using the psaA gene placed this isolate within the Scytosiphonaceae. It does not confirm the exact identification of R. orientalis, although its placement close to other Rosenvingea sequences was confirmed and morphological evidence supports its placement in R. orientalis. Our culture investigations indicated that it has an asexual life cycle. Further collections are needed to resolve the full generic and specific relationships of Rosenvingea and related taxa, and their reproductive patterns.