Jania is a genus of red macroalgae (or seaweeds) with hard, calcareous, branching skeletons in the family Corallinaceae.
Taxonomy and Nomenclature The genus name of Jania is derived from the Greek water nymph called Ianeira (or Janeria). It was first circumscribed by Jean Vincent Félix Lamouroux in 1812. Based on a recent integrated taxonomic examination of the genus, and by extension its tribe Janieae, the members of Cheilosporum and Haliptilon have all been transferred under genus Jania. As a result, there is currently around 55 confirmed species for this genus.
Morphology Jania is an articulated coralline algae characterized by having erect thalli with dichotomously-arranged branches composed of alternating segments of red or pink, calcified, cylindrical sections (intergeniculum) and white uncalcified sections (geniculum); that is attached to the substrate by small, stolon-like holdfasts. Intergenicula of this genus can be cylindrical, subcylindrical or compressed and smooth, winged or lobed.
Distribution Jania species are well-distributed throughout the world.
Ecology Members of the genus are found in sheltered reef habitats, often in crevices or other shaded areas.Segmented algae (Jania spp.) Marine Species Identification Portal. Retrieved 2011-12-31. They are also epilithic, epiphytic, and could form free-living clumps called articuliths.
Life history Like most red seaweeds, Jania exhibit a triphasic life cycle wherein aside from the free-living haploid (gametophyte) and diploid (tetrasporophyte) generations, another diploid generation that is parasitic to the gametophyte, the carposporophyte. Tetrasporophyte (2N) generation would release four haploid spores (or tetraspores) that would later on develop into either the male and female gametophytes; moreover, the spermatium (N) produced by the spermatangia will be trapped by the trichogyne of the carpogonium (N) of the female gametophyte and later on fuse to form the zygote and subsequently develop into the carposporophyte (2N); lastly the carposporophyte will produce carpospores (2N) that will become the tetratsporophyte (2N). The unique structure involved in coralline reproduction is the presence of the conceptacle, a calcified depression wherein the tetrasporangia, spermatangia, and carposporangia are formed.
Exploitation/harvesting/cultivation There is no known cultivation technology for this genus.
Chemical composition/natural products chemistry Priming tomato seeds with Jania polysaccharides has shown to greatly improve the resistance of seedlings to soil-borne pathogens and consequently promote plant growth.
Utilization and management Despite the potential use of Jania in agriculture and due to a lack of interest on this genus, this genus is not currently being commercially utilized.
Species The World Register of Marine Species list the following:
Jania acutiloba (Decaisne) J.H. Kim Jania adhaerens J.V.Lamouroux, 1816 Jania affinis Harvey, 1855 Jania arborescens (Yendo) Yendo, 1905 Jania articulata N'Yuert & Payri, 2009 Jania capillacea Harvey, 1853 Jania crassa J.V.Lamouroux, 1821 Jania cristata (Linnaeus) Endlicher, 1843 Jania cubensis Montagne ex Kützing, 1849 Jania cultrata (Harvey) J.H. Kim Jania decussatodichotoma (Yendo) Yendo, 1905 Jania fastigiata Harvey, 1849 Jania intermedia (Kützing) P.C.Silva, 1996 Jania iyengarii E.Ganesan, 1966 Jania lobata Zanardini, 1858 Jania longiarthra E.Y.Dawson, 1953 Jania longifurca Zanardini, 1844 Jania micrarthrodia J.V.Lamouroux, 1816 Jania minuta Johansen & Womersley, 1994 Jania nipponica (Yendo) Yendo, 1905 Jania novae-zelandiae Harvey, 1855 Jania pacifica Areschoug, 1852 Jania parva Johansen & Womersley, 1994 Jania prolifera A.B. Joly, 1966 Jania pulchella (Harvey) Johansen & Womersley, 1994 Jania pumila J.V.Lamouroux, 1816 Jania pusilla (Sonder) Yendo, 1905 Jania pygmaea J.V.Lamouroux, 1816 Jania radiata Yendo, 1905 Jania rosea (Lamarck) Decaisne, 1842 Jania rubens (Linnaeus) J.V.Lamouroux, 1816 Jania rubrens (L.) Lamour Jania sagittata (J.V.Lamouroux) Blainville, 1834 Jania santae-marthae Schnetter Jania spectabile (Harvey ex Grunow) Jania squamata (Linnaeus) J.H. Kim, Jania subpinnata E.Y.Dawson, 1953 Jania subulata (Ellis & Solander) Sonder, 1848 Jania tenella (Kützing) Grunow, 1874 Jania ungulata (Yendo) Yendo, 1905 Jania verrucosa J.V.Lamouroux, 1816 Jania yenoshimensis (Yendo) Yendo, 1905
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