N_YEURT.fm Page3 Mercredi,3.février2010 5:0517 Cryptogamie,Bryologie,2010,31(1):3-205 ©2010Adac.Tousdroitsréservés Marine algal flora of French Polynesia III. Rhodophyta, with additions to the Phaeophyceae and Chlorophyta AntoineD.R.N’Yeurta*&ClaudeE.Payria,b aUMR7138,Systématique,Adaptation,Evolution,EquipeBiodiversitéMarine Tropicale,IRD-Nouméa-BPA5,98848Nouméacedex,NewCaledonia bLaboratoireTerre-Océan,UniversitédelaPolynésiefrançaise,B.P.6570Faa’a 98702,Tahiti,FrenchPolynesia (Received8October2009,Accepted23December2009) Abstract—ThisthirdpaperinamonographicseriesonthemarinemacroalgaeofFrench PolynesiagivesadetailedcoverageofthespeciesofRhodophytaoccurringintheseislands. Atotalof197taxaarepresented(195Rhodophyceae,1Phaeophyceaeand1Chlorophyta; ofthese,84(or43%)representnewrecordsfortheflora,while7(or3.6%)arenewspecies. The new combination Jania subulata (J. Ellis et Solander) N’Yeurt et Payri is made for Haliptilon subulatum (J. Ellis et Solander) W. H. Johansen. Padina stipitata Tanaka et Nozawa (Phaeophyceae) and Codium saccatum Okamura (Chlorophyceae) are notable additionstotheflorafromdeepwaterhabitatsinthesouthernAustrals;56taxa(or28.7%) occuronlyintheAustralarchipelago.TheflorahasmostaffinitieswiththatoftheHawaiian Islands(SørensenIndex=0.30),followedbytheCookIslandsandSamoa(SI=0.26each) and the Solomon Islands (SI = 0.25). There are some disjunct distribution patterns for severalsubtropicaltotemperatespecies,possiblysuggestingspecialoceaniccurrentroutes betweenthesouthernAustrals,HawaiiandtheSouthernAustralianregion. algae / biogeography / distribution / floristics / French Polynesia / Rhodophyceae / new records/taxonomy Résumé — Ce troisième volet d’une étude sur la flore marine de la Polynésie française donneunedistributiondétailléedesespècesdeRhodophycéesquisontprésentesdansces îles. Un total de 197 taxons sont présentés (195 Rhodophycées, 1 Phaeophycée et 1Chlorophycée), dont 84 (soit 43 %) sont nouveaux pour la flore, et 7 (soit 3,6 %) représentent des nouvelles espèces. La nouvelle combinaison Jania subulata (J. Ellis et Solander) N’Yeurtet Payri est faite pourHaliptilon subulatum(J. Elliset Solander) W.H. Johansen. Padina stipitata Tanaka et Nozawa (Phaeophyceae) et Codium saccatum Okamura (Chlorophyta) sont nouveaux pour la flore, provenant d’habitats profonds dans les îles les plus sud des Australes; 56 taxons (ou 28,7 %) ont été trouvés seulement dans l’archipel des Australes. La flore a le plus d’affinités avec l’archipel Hawaiien (Index de Sørensen de 0,30), suivi par les îles Cook et Samoa (SI = 0,26 chaque) puis par les îles Salomon(SI=0,25).Unerépartitiondisjointepourunnombred’espècessous-tropicalesà tempérées suggèrerai un lien particulier par les courants océaniques entre l’archipel des Australesdusud,l’archipelHawaiienetlarégionsud-australienne. algae / biogéographie / distribution / floristique / Polynésie Française / Rhodophyceae / nouveauxreports/taxonomie * Correspondenceandreprints:[email protected] Communicatingeditor:FrederikLeliaert N_YEURT.fm Page4 Mercredi,3.février2010 5:0517 4A. D.R.N’Yeurt&C.E.Payri INTRODUCTION ThisstudygivesadetailedoverviewofthemarinespeciesofRhodophyta (along with two new records of Phaeophyceae and Chlorophyta) occurring in French Polynesia, and supplements and revises the taxa previously reported by Setchell, (1926), Payri & Meinesz (1985a, b), Payri & N’Yeurt (1997), Payri et al. (2000) and Conte & Payri (2002, 2006). The Phaeophyceae and Chlorophyta of French Polynesia, as well as the history of early phycological collecting in these islands,weretreatedinPayri&N’Yeurt(1997)andN’Yeurt&Payri(2006,2007). MATERIALSANDMETHODS All material was collected using SCUBA, dredging, snorkelling or reef- walking. Herbarium specimens were pressed using standard techniques, and representative parts of thalli and turf algae stored in 4% buffered formalin in sealed plastic bags packed in a light-proof container for shipment and later anatomical examination in the laboratory. Herbarium specimens were photographed using a bench-mounted digital camera (NIKON Coolpix 995). Photomicrographs were obtained using OLYMPUS C-4040Z or C-5050Z digital cameras fitted on an OLYMPUS BH2 microscope. Voucher specimens are housed at the Phycological Herbarium of the Université de la Polynésie française in Tahiti (UPF), with ‘S’ referring to slide collections, and can also be viewed online at the following Internet address: http://biodiv.upf.pf/base (link at times subject to outages). ‘IFR’ refers to holdings in the herbarium of the French Institute of Research on Coral Reef Environment (IFRECOR) in Bora Bora, French Polynesia (curated by Mr. Denis Schneider). Where necessary, available FrenchPolynesianherbariumrecordsinUPFhavebeenre-verifiedinthelightof newtaxonomicinformation,andsomebyWilliamSetchellandH.E.Parksaswell as other early collections in BM (British Museum, London), PC (Museum National d’Histoire Naturelle, Paris), SAP (Hokkaido University, Sapporo) and UC(UniversityofCalifornia,Berkeley)examinedeitheronsiteoronloanbythe first author. Unfortunately, some voucher specimens of species from Moorea listed in Payri (1987), which contain some taxa not held at UPF, could not be located and are presumed lost. Consequently, only those records which could be confirmed on the basis of existing collections, either in UPF or elsewhere, have been included in this study. Recent new records from a deepwater survey by the authors of the island of Moorea in the context of a genetic barcoding program by the University of California Gump Research Station, have been included in this publication. The taxonomy generally follows that of Silva et al., (1987; 1996), Reviers(2003),andisupdatedwithothersourceswherenecessaryasstatedinthe text.Foreachtaxon,basionymandtypelocalityinformationisprovided,followed byrelevantsynonymsandbibliographicreferences(mostlyrestrictedtothosethat are regional, tropical or contain pertinent diagnostic figures). Asterisks (*) indicate new records for French Polynesia. N_YEURT.fm Page5 Mercredi,3.février2010 5:0517 MarinealgalfloraofFrenchPolynesiaIII.Rhodophyta, 5 withadditionstothePhaeophyceaeandChlorophyta RESULTSANDOBSERVATIONS Key to the genera of French Polynesian Rhodophyta 1a. Thallus internally calcified, even lightly so (bubbles when tested with weak acid) .............................................................2 1b. Thallustotallyuncalcified ..........................................19 2a. Thallussegmented ...............................................3 2b. Thallusunsegmented.............................................8 3a. Thalluscalcifiedatsegmentjoints ..........................Tricleocarpa 3b. Thallusuncalcifiedatsegmentjoints ..................................4 4a. Axescompressedtoflattened;segmentswithupward-curvinglobes .....5 4b. Axestereteorcompressed;segmentsnotcurvingupward..............7 5a. Thallusdichotomouslybranched,axesflattened,1-6mmwide .. Jania(inpart) 5b. Thalluspinnatelybranched,axescompressed,0.3-1mmwide.............6 6a. Intergenicula 0.3-0.5 mm wide, main axes percurrent, less than 9 tiered medullarycellsperintergenicula ....................... Jania(inpart) 6b. Intergenicula 0.5-1 mm wide, main axes not percurrent, more than 10 tieredmedullarycellsperintergenicula.......................Corallina 7a. Axes usually terete, less than 150µm in diameter; conceptacles located at nodesjustbelowdichotomies ............................ Jania(inpart) 7b. Axes compressed to terete, more than 500µm in diameter; conceptacles scatteredoninternodesurface ...............................Amphiroa 8a. Thallusflabellate,withskin-liketexture...................Titanophora 8b. Thallusnotasabove..............................................9 9a. Thalluswithringsofverticillatehairsaroundbranches........ Actinotrichia 9b. Thalluswithoutverticillateringsofhairsaroundbranches. ..............10 10a. Tipsofultimatebranchesuncalcified...............................13 10b. Thalluscalcifiedthroughout,includingtips .........................11 11a. Thallusstone-likeorcrustose ...................... Corallinales(inpart) 11b. Thallusnotstone-likeorcrustose....................................12 12a. Axesrigid,sometimesvillous,to3mmwide ........................18 12b. Axessoftandgelatinous,glabrous,to10mmwide............ Renouxia 13a. Cortical cells distinctly inflated or club-shaped; carpogonial branch straight, 3-celled,calcificationannulate ............................. Yamadaella 13b. Cortical cells not distinctly inflated or clavate; carpogonial branch curved, 3-6-celled,calcificationsmoothorpowdery,notannulate................14 14a. Calcification clearly restricted to axial core, surrounded by mucus; spermatangiainwhorlsonsubapicalcells,neverterminal;sterilefilaments issued from base of carpogonial branch making dense, non-involucral clustersbelowcystocarp ................................ Trichogloea 14b. Calcification diffuse, not restricted to axial core or covered by mucus; spermatangia usually terminal, not in subapical whorls; sterile filaments N_YEURT.fm Page6 Mercredi,3.février2010 5:0517 6A. D.R.N’Yeurt&C.E.Payri from carpogonium either absent or making long involucres around cystocarp...................................................... 15 15a. Medullaryfilamentslessthan30µmindiameter,carpogonialbrancheslateral on subterminal cortical cells; cystocarps with long involucres of sterile filamentsissuedfromcarpogonialbranch;spermatangiasingle,inclustersor innon-dendroidpairs ............................................. 16 15b. Medullary filaments more than 40µm in diameter; carpogonial branches on filaments at base of cortical fascicles; cystocarps lacking long involucres of sterilefilaments;spermatangiaindenseelongate-ovoidheads....Ganonema 16a. Axeslackingshortlateralbranchlets;outercorticalfilamentsunbranched; gonimoblastobconical;spermatangiaindenseclusters......Titanophycus 16b. Axes with or without short lateral branchlets; outer cortical filaments profusely branched; gonimoblast spherical; spermatangia on outermost corticalfilaments.......................................... Liagora 17a. Thalluscrustose,withmoreorlesspronouncedhypobasalcalcification..... ....................................................... Peyssonnelia 17b. Thallusnotcrustoseandlackinganyhypobasalcalcification ............ 18 18a. Tetrasporangiaterminalonelongatefilaments;pericarpabsent...Galaxaura 18b. Tetrasporangialateralorterminalonstalkcells;pericarppersistent ..... .................................................... Dichotomaria 19a. Thallusconsistingofasinglerowofcells. ............................ 20 19b. Thallusconsistingofmorethanonerowofcells. ...................... 23 20a. Thalluslessthan5mmhigh,ofsubquadratecells ................... 22 20b. Thallusmorethan5mmhigh,cellsnotsubquadrate................. 21 21a. Cellssubcylindrical .......................................Anotrichum 21b. Cellsoval ................................................ Griffithsia 22a. Thalluslessthan500µmhigh,entirelyuniseriate,unbranched .......... .................................................... Erythrotrichia 22b. Thallus1-5mmhigh,multiseriateinolderparts,irregularlybranched ....................................................... Stylonema 23a. Innerstructurefilamentousorsemi-filamentous...................... 25 23b. Innerstructurecellular,orcellularwithsparsehyphae................. 24 24a. Thallushollow,vesicle-likeorseptatewithregulardiaphragms. ....... 36 24b. Thallussolidthroughout ........................................ 41 25a. Axeslessthan2mmindiameter,growinginestuariesandrivermouths .. 26 25b. Axesover4mmindiameter,notgrowinginestuariesandrivermouths .. 27 26a. Filamentsconfinedtocenterofaxis;branchingregularlydichotomouswith unconstrictedbranchbase;tetrasporangiazonatelydivided....Sarconema 26b. Filaments not confined to center of axis; branching irregular with constrictionsatbaseofbranches;tetrasporangiacruciatelydivided ...... ......................................................Grateloupia 27a. Thallusformingclumpsofcrisp,roundedrosettes10-15mmwide.......... ....................................................... Cryptonemia 27b. Thallusnotinclumpsorformingrosettes ............................ 28 N_YEURT.fm Page7 Mercredi,3.février2010 5:0517 MarinealgalfloraofFrenchPolynesiaIII.Rhodophyta, 7 withadditionstothePhaeophyceaeandChlorophyta 28a. Thallusprocumbent,withmultipleattachmentpoints .......Meristotheca 28b. Thalluserect,withasinglebasalholdfast...........................29 29a. Thallusterete.....................................................35 29b. Thallusstrap-shaped,blade-likeorglobose ...........................30 30a. Thallusblade-like...............................................31 30b. Thallusstrap-shapedorglobose,notformingblades .................32 31a. Atleastsomeanticlinal(cortextocortex)filamentspresent ..... Halymenia 31b. Anticlinalfilamentsabsent;thallususuallyperforate ...........Kallymenia 32a. Axesstrap-shaped,complanate,3-4mmwide,withroundedapices. ...... .....................................................Corynocystis 32b. Thallusglobose,notcomplanate ..................................33 33a. Holdfastdiscoidorcartilaginous;tetrasporangiacruciate,lateralonterminal cellsofcorticalfilaments ...................................Gibsmithia 33a. Holdfastnevercartilaginous ........................................34 34a. Corticalcellsrectilinear;sphericalnutritivecellspresentbelowcystocarp . .........................................................Predaea 34b. Corticalcellsovoid;nutritivecellsabsentbelowcystocarps...... Platoma 35a. Main axis percurrent; higher-order branches spindle-shaped; cells of carpogonial branch subrectangular, without a thick mucilaginous coating; carposporangialmassfullyencirclingauxiliary-cellfilament ... Peleophycus 35b. Main axis not percurrent; higher-order branches not spindle-shaped; cells of carpogonial branch sub-moniliform with a thick mucilaginous coating; carposporangialmassincompletelyencirclingauxiliary-cellfilament........ ........................................................ Dudresnaya 36a. Thallus regularly segmented; diaphragms present; cells barrel-shaped, irregularlybranchedandfree...............................Champia 36b. Thallus not regularly segmented; diaphragms absent; cells vesicle-like; simplesaccateordichotomouslybranchedandlaterallyfused .........37 37a. Thallusdifferentiatedintoacreepingstolon,stipeandovoidvesicles ....... ........................................................Botryocladia 37b. Thallusnotdifferentiatedintoacreepingstolon,stipeandvesicles .......38 38a. Thallusovoid,consistingoffreeorfusedvesicles ....................40 38b. Thallusterete,consistingofwiryorarcuateaxes. ....................39 39a. Thalluslessthan5mmhigh,creeping;branchesarcuateandpinkish........ .........................................................Lomentaria 39b. Thallusto40mmhigh,erect;branchesstraightandiridescentblue... Coelothrix 40a. Thallusdichotomouslybranched;vesiclesovoid,fusedlaterally. ......... ................................................... Chamaebotrys 40b. Thallussaccate,simpletofurcate,spindle-shaped,notfusedlaterally..... .................................................... Gloiosaccion 41a. Ultimatebranchesflattenedorleaf-like ..............................42 41b. Ultimatebranchesnotflattenedorleaf-like...........................53 42a. Thallus forming rosettes, differentiated into a rigid naked stem and leaf- likeultimatebranchletswithamidribandinrolledtips .........Amansia N_YEURT.fm Page8 Mercredi,3.février2010 5:0517 8A. D.R.N’Yeurt&C.E.Payri 42b. Thallus not forming rosettes or differentiated into a rigid stem and leaf- likeultimatebranchletswithinrolledtips .......................... 43 43a. Thallusconsistingoffelt-likelobesandanetworkoffilaments ..Haloplegma 43b. Thallusnotfelt-likeorcomposedofanetworkoffilaments............. 44 44a. Thallusstrap-shapedorcompressed............................... 48 44b. Thallusfolioseorblade-like ..................................... 45 45a. Thallusprocumbentanddorsiventral,withacentralkeel-likeregion....... ...................................................Dasya palmatifida 45b. Thallusnotasabove .............................................. 46 46a. Thallusiridescent,flabelliformandanastomosing,withacentralstipe.. 47 46b. Thallus not iridescent, flabelliform or anastomosing; stipe basal or marginal ...................................................... 49 47a. Thallusfoliose;tetrasporangiaterminal,carpogonialbranch3-celled....... .........................................................Halichrysis 47b. Thalluspeltate;tetrasporangiaintercalary;carpogonialbranch4-celled..... ................................................Asteromenia (inpart) 48a. Thallusstrap-like;axes1-2mmwide;medullarycells60-150µmwide .... ..............................................Asteromenia (inpart) 48b. Thalluscompressed;axesto150µmwide;medullarycells10-18µmwide . .....................................................Caulacanthus 49a. Thallusdelicateandthin,membranous(atleastinpart)................ 50 49b. Thallus thick and blade-like and/or subdichotomously branched, cells rounded................................................ Rhodymenia 50a. Midribpresent;pluristromaticandbranchedatthemidrib.. Hypoglossum 50b. Midribabsent.................................................. 51 51a. Thallusmonostromaticthroughout;ofunbranchedlobes...... Nitophyllum 51b. Thalluspluristromatic. ............................................ 52 52a. Branchingirregularlyalternatefrommargins;tetrasporangiainsori ..... ....................................................Myriogramme 52a. Branching pinnate to subdichotomous; tetrasporangia in whorls on side branchlets....................................Acanthophorapacifica 53a. Thallusplumose,withapinkishnakedcreepingstolonanderectaxes ...... .......................................................Asparagopsis 53b. Thallusnotplumose .............................................. 54 54a. Thallusterete(includingturf-likeminuteforms).................... 56 54b. Thalluscompressedtoflattened,notturf-like ...................... 55 55a. Thallus erect and lubricous, alternately branched; tetrasporangia zonate, in elongatestichidia;noparticularlypungentodourwhenfresh.... Plocamium 55b. Thallusprostrate,notlubricous;bilaterallybranched;tetrasporangiacruciate tozonate,innemathecia;pungentodourwhenfresh..............Portieria 56a. Thallus2-20cmhigh,erectandnon-epiphytic ...................... 57 56b. Thalluslessthan2cmhigh,oftencreepingorepiphytic.............. 74 N_YEURT.fm Page9 Mercredi,3.février2010 5:0517 MarinealgalfloraofFrenchPolynesiaIII.Rhodophyta, 9 withadditionstothePhaeophyceaeandChlorophyta 57a. Thallus unbranched in lower portions but irregularly branched above; side branchletsshortandtruncate,alternatelytoradiallyarranged ...........58 57b. Thallusnotasabove...............................................61 58a. Incross-section,axialcellsurroundedclearlyby5largepericentralcells .. ....................................................... Chondria 58b. Incross-section,axialcellnotclearlysurroundedby5pericentralcells. 59 59a. Axialcellwithonly2pericentralcells;axesbroadandflattened............ .....................................................Chondrophycus 59b. Axialcellwith4pericentralcells;axesteretetocompressed............ 60 60a. Apicalcellsunkeninapicalpit;centralaxisunclearexceptatapex ....... ........................................................ Palisada 60b. Apicalcellnotsunkeninapicalpit;centralaxisrelativelyclear....Laurencia 61a. Thalluscomposedofwiryaxes,moreorlessrigid ......................62 61b. Thallusnotwiryorparticularlyrigid .................................64 62a. Thallus greenish-yellow, tough and wiry with oppositely-branched axes, formingdecumbentclumpsonthereefcrest ..........Gelidiella(inpart) 62b. Thallusnotdecumbentorasabove................................63 63a. Axes400-500µmindiameter;mostlybranchedatapices,whichturnyellow. . ....................................................... Ahnfeltiopsis 63b. Axes150-300µmindiameter;unbranchedatapices,notturningyellow ..... ...................................................... Wurdemannia 64a. Thallus flexible; axes terete or compressed and distally palmate; tetrasporangiainterminalbulb-likeswellings ...............Gelidiopsis 64b. Thallusnotasabove.............................................65 65a. Thallus reddish-brown; ultimate branches strap-shaped or terete; internal rhizinespresent;apicalcellconspicuousandexserted...................66 65b. Thalluswithoutinternalrhizinesorconspicuousapicalcell..............67 66a. Branchingalternatetoopposite;branchapextruncateorblunt .......... ....................................................Pterocladiella 66b. Branchingpinnate;branchapextaperedandfiliform,pointed ...Gelidium 67a. Thallus of sparsely and alternately branched axes issued from a creeping base;growingasadensetuftoncoraldebris...........................68 67b. Thallusnotasabove...............................................69 68a. Axial and periaxial cells in clear transverse rows; sporangia in sparse, regularlyarrangedrows.................................Parviphycus 68b. Axial and periaxial cells irregularly disposed; sporangia not arranged in regularrows......................................Gelidiella(inpart) 69a. Thallus terete and brittle, uniformly covered with short knobby spine-like branchlets..................................... Acanthophora(inpart) 69b. Thallusnotasabove...............................................70 70a. Thallusfurry,withaxescoveredwithfinefilamentoussidebranchlets...71 70b. Thallusnotfurry................................................72 71a. Filamentoussidebranchletsregularlycorticatedatthenodesonly;tetrasporangia non-involucrateandprotrudingonsidesofbranchlets................ Spyridia N_YEURT.fm Page10 Mercredi,3.février2010 5:0517 10A. D.R.N’Yeurt&C.E.Payri 71b. Filamentous side branchlets uncorticated; tetrasporangia involucrate and occurringinspecializedfusiformstichidia ................. Dasya(inpart) 72a. Thallusregularlydichotomouslybranched,tree-like,withabasalstipe... ......................................................Dermonema 72b. Thallusnotasabove............................................ 73 73a. Branches terete or flattened, arcuate or straight; proliferous side branchlets absent;tetrasporangiacruciateandscatteredinoutercortex......Gracilaria 73b. Branches terete or flattened; always arcuate; proliferous side branchlets sometimespresent;tetrasporangiazonateandoccurringinsaddle-shapedsori ontheundersideofbranchlets..................................Hypnea 74a. Thallus soft and rubbery, composed of compressed, elongate lobes with short, irregularly distichous side branchlets and strap-like rhizoids issued fromventralsurfaceofblades............................ Gloiocladia 74b. Thallusnotasabove............................................ 75 75a. Mainaxislackingpericentralcellsaroundaxialcell.................... 76 75b. Mainaxiswithfourormorepericentralcellsaroundaxialcell........... 77 76a. Erect axes sparsely branched, covered with three whorls of upwardly- curvedsidebranchletsperaxialcell......................... Crouania 76b. Erect axes alternately to radially branched; whorls of side branchlets absent ................................................. Seirospora 77a. Main axes partially or fully covered with small cortical cells 8-10µm in diameter;terminalandlateraltrichoblastsneverpresent ............... 78 77b. Main axes never covered with small cortical cells; terminal and lateral trichoblastsoftenpresent.......................................... 82 78a. Axesfullycorticated............................................ 79 78b. Axescorticatedatthenodesonly. ................................ 81 79a. Thallusminute,lessthan2mmhigh,epiphyticonlyonLobophora......... ........................................................ Phaeocolax 79bThallusmorethan3mmhigh,notepiphyticonlyonLobophora.......... 80 80a. Tipofaxespointed;nodalspinesabsent .................. Corallophila 80b. Tipofaxesclaw-likeorforcipate;nodalwhorlsofspinespresent. ....... ...................................................... Centroceras 81a. Basipetalcellsdistinctlyelongate ..............................Gayliella 81a. Basipetalcellsangular,notelongate.......................... Ceramium 82a. Axeswithterminaland/orlateraltrichoblasts...................... 84 82b. Axeswithoutterminalorlateraltrichoblasts ....................... 83 83a. Thallus erect and irregularly dichotomously branched, with dichotomously branchedsidebranchletsissuedfromeveryothersegment... Heterosiphonia 83b. Thalluscreeping,witherectunbranchedaxes...................... Ditria 84a. Thallus composed of a creeping, often incurved main axis from which are issuedseveralerectsimplebranchlets .................. Herposiphonia 84b. Thallus mostly erect and irregularly branched, never with an incurved mainaxis. ..................................................... 85 N_YEURT.fm Page11 Mercredi,3.février2010 5:0517 MarinealgalfloraofFrenchPolynesiaIII.Rhodophyta, 11 withadditionstothePhaeophyceaeandChlorophyta 85a. Rhizoids separated by a cross-wall from the supporting pericentral cells; tetrasporangiainspiraledseries;spermatangialbrancheswithasterilelateral ........................................................Neosiphonia 85b. Rhizoids in open connection with the pericentral cells; tetrasporangia in straightseries;spermatangialbrancheslackingasterilelateral . Polysiphonia RHODOPHYTA R. Wettstein StylonematalesK.M.Drew StylonemataceaeK.M.Drew StylonemaReinsch The taxonomy of this and other related red algal genera was recently revisedbySaunders&Hommersand(2004),takingintoaccountrecentmolecular data. *Stylonema alsidii (Zanardini) K.M. Drew, 1956: 72. Indian Ocean: Silva et al., 1996:87;HawaiianIslands:Abbott,1999a:44,fig.1B-C;Oman:Wynne,1999:189; Samoa:Skelton&South,2002a:137,fig.3A-B;2007:12,figs9-10;PacificIslands: Zucarelloetal.,2008:390. (Figs1-2) Basionym:BangiaalsidiiZanardini,1840:136(typelocality:Trieste,Italy). Homotypicsynonym:Goniotrichumalsidii(Zanardini)M.Howe1914:75.Tristan da Cunha: Baardseth, 1942: 33, fig. 13A-B; Venezuela: Díaz-Piferrer, 1970: 170, fig.22. Materialexamined:Rapa,Australs,10Oct.2000,leg.V.Clouard,UPF3253RPS57. Thallus to 5 mm high and 12-15µm in diameter, filamentous and basally uniseriate, with some older parts multiseriate. Branching simple or irregular. Remarks: Epiphytic on Fernandosiphonia sp.; to date in French Polynesia only reported from a single collection from the island of Rapa, southern Australs. RecentphylogeneticstudiesbyZucarelloetal.(2008)haveshownS.alsidiitobea trulyubiquitousspecies. Erythropeltidales Garbary et al. ErythrotrichiaceaeG.M.Smith ErythrotrichiaAreschoug *Erythrotrichia carnea (Dillwyn) J. Agardh, 1883: 15. Indian Ocean: Silva et al., 1996: 88; Rotuma Island: N’Yeurt, 1996: 406, figs 109, 118; Hawaiian Islands: Abbott, 1999a: 45, fig. 1E; Fiji: N’Yeurt, 2001: 746, fig. 106; Samoa: Skelton & South,2007:11,fig.8. (Figs3-4) Basionym: Conferva carnea Dillwyn, 1807: pl. 84 (type locality: Glamorgan, Wales). Material examined: Taapuna, Tahiti, 15 Sep. 1995, leg. A. D. R. N’Yeurt, UPF 438 S52; Rapa,Australs,4Nov.2002,leg.C.E.Payri,UPF3421RPS203. Thallus entirely uniseriate, to 500µm long and 10-25µm in diameter, composed of cells isodiametric to cylindrical at the base, gradually becoming longerandbroaderupwards.Attachedtothesubstratumbyacharacteristiclobed extension of the basal cell. Remarks: Epiphytic on Padina (lagoon, Tahiti) or on Sargassum (rocky shelves, Rapa). This species can be differentiated from Stylonema alsidii by its entirely uniseriatethallusattachedviaalobedextensionofthebasalcell. N_YEURT.fm Page12 Mercredi,3.février2010 5:0517 12A. D.R.N’Yeurt&C.E.Payri Figs 1-6. 1. Stylonema alsidii: habit of irregularly branched thallus (UPF 3253). Scale = 15µm. 2.Stylonema alsidii: detail of cells of filament (UPF 3253). Scale = 15µm. 3. Erythrotrichia carnea:habit(UPF3421). Scale=20µm.4.Erythrotrichiacarnea:detailofrectangularcellsof upper thallus (UPF 3421). Scale = 15µm. 5. Acrochaetium barbadense: habit, showing adaxial monosporangia (arrow) (UPF 3425). Scale = 70µm. 6. Acrochaetium microscopicum: habit on Polysiphoniahost(UPF3424).Scale=25µm.