Table Of Content

Nuytsia9(1):91-94(1993) 91 A new species ofRestionaceae from south-western Western Australia K.W. Dixon1 K.A. Meney'andJ.S. Pate2 , 'KingsParkandBotanicGarden,WestPerth,WesternAustralia6005 2BotanyDepartment,UniversityofWesternAustralia,Ncdlands,WesternAustralia6009 Abstract Dixon, K.W.,Meney, K.A, and Pate,J.S. A newspeciesofRestionaceaefrom south-western Western Australia. Nuytsia 9(1): 91-94 (1993). Restio isomorphus is a new species ofAustralian Restionaceaefromarestrictedareainthesouth-westofWesternAustralia. Rhizomemorphologyand ecological factors likely to influencetheconservation status ofthis species arediscussed. Introduction WesternAustraliacontainsapproximately 110speciesofRestionaceaerepresentingoverthree- quarters ofthe known Australasian species. However, sincethepublication ofCarlquist(1976)and morerecently, Briggs etal. (1990), there has been no published description ofnew taxain Western AustraliapendingresolutionofthegenericclassificationoftheAustralianRestionaceaebyDrB.G. Briggs and DrL.A.S. Johnson. This paper describes one ofa suite ofspecies collected as part of a broad-based botanical and ecological survey ofthe family in Western Australia(Meney & Dixon 1988, Meney, Pate & Dixon 1990a, Meney, Pate & Dixon 1990b, Pate, Meney & Dixon 1991). Most of the new taxa are geographically restricted, are limited to a few individuals in vulnerable habitats and/or are fire- sensitive. Thusspecialmanagementconsiderationswillbenecessarytoensurethelong-termsurvival ofthespecies. Restioisomorphus K.W. Dixon and K.A. Meney, sp. nov. (Figure 1) Planta dioica spicis maribus femineisque similibus, rhizomate breviter repente, tomentoso, culmis erectis, viridibus, sparsim ramosis; culmorum vaginae ad basim purpurescentes, lateralibus marginibus expansis. Typus: South-westernWesternAustralia,South-westBotanicalProvince,ScottRiveralongGovernor BroomeRoad and Dennis Road (115° 17' E, 34° 15' S), December 1988, Meney& Dixon (KM 110, female plant) (holotype: PERTH; isotype: K, SYD). Growing in shallow sandy soils over lateritic ironstone often with aperched water-tableduring winterand spring. Habit. Plants tuftingtoshortlycreeping, 45 cm indiameter, roughly circular. 92 NuytsiaVol.9,No. 1 (1993) sFpiigkuerleet1(.xR5e)s;ti5o-ifseommaolrepfhluosw.er1o-pseknetecdhoouftp(lxa5n)t;(6x-0m.a25l)e;sp2ik-eslinegtl(ex5f)e;ma7le-cmuallemf(lx0o.w5e)r;o3pe-nseindgoluetm(axl5e);cu8l-mrh(xi0z.o5m);e4an-dfelmoawleer culmbases(x0.5); 9-culmsheath(x2). K.W.Dixon. K.A.MeneyandJ.S.Pate,Restioisomorphus 93 Rhizome elongated,variableinlength,2-3mmindiameter,denselyvillousonyoungrhizomesbut weatheringwithage,withbroadlydeltoid,closelyappressedscaleleaves,0.3-0.4mmlong,glossyand deciduous. Cataphylls 2-4,7-14mm long,straw-coloured, closelyappressed, chartaceous,acuteto mucronate and persistent. Culms simple, glabrous, green flushed with purple at internodes, finely striate,60-70cmtall, 1-1.2mmwide,erectandparallel,solid,chlorenchymaoftwolayersofpalisade cells, stomatasuperficial. Culmsheaths 5-7, sterile and9-14fertileperculm, 1.5-2.1 cm long with a 1-2mmlongoftendeciduousmucro,appressedatbasewithflaredlateralmargins,striate,scarious, mm mm purple grading tofawn towardsapex, persistent. Malespikeletserect, ovoid, 3-4 long, 2-3 wide,2-3persubtendinginflorescencebractonshort 1-2mmlongpedicels;subtendinginflorescence bractbroadlyobovate,2-3mmlongwitha 1 mmlongmucro;lower 1-2glumesinfertile,upper 10-25 glumesfertile,glossy,coppery-bronzeaginggrey,marginsentire. Maleflowers sub-sessile;tepals5, 2outerand3 inner,2.5 mm long, linear-lanceolate,flat; marginspale,membranouswithrust-brown tips,lateraltepalskeeled,glabrous,innertepalsslightlyshorterandbroader. Stamens3,stout,exserted, pistallodeabsent. Femalespikeletserect,narrow-ovoidtoovoid,5-7mmlong,1-1.8mmwide,sessile; bracts4, usually all fertile,sub-equal,keeled,red-brown, 3-5 mm longwitha 1 mm long mucroand shortly fimbriate margins; spikelets solitary in upper 5-8 subtending inflorescence bracts, lower inflorescence bracts often subtending 1.5-7 cm long branches each terminating in 3-6(8) single spikelets;subtendinginflorescencebractssimilartothoseonmaleplants. Femaleflowers: tepals5(6), linear-lanceolate,acute,3-3.5mmlong,paletohyaline,outertepalskeeledwithhairs,innertepalsonly slightlykeeled andglabrous; stylered,dividedtobasewith two style branches, stigmawhite, ovary bFirluoictulaarc,ap1sumlem, gwliodses,y,1.c2hemstmnultonbgr,ocwonmptoredsasrekdbwriotwhn,tw1o.8l-a2t.e0raml mraiwsieddes.utuSreeesd; ssmtaalmli,no1d.5esxa1bsmenmt,. reniform, black, with whiteridges. Floweringperiod. LateFebruary toApril; seeddehiscence: November-December. Affinities.RestioisomorphusshowsaffinitywithRestio stenandra (BriggsandJohnsonined.)inplant habit and spikelet morphology but is distinct in possessing superficially similar male and female spikeletsandintheflaredpurpleandfawnculmsheaths. Thespeciesfavoursshallowwhiteorredsandy soilsover lateritic ironstone whichisseasonally wet. Theculmsareerectandarisefrom a 1.5-2cm deepsubsurfacemoreorlesscreepingrhizome. TherhizomemorphologyfitscategorytypeB3(Pate, MeneyandDixon 1991)anddoesnotcontainstarch. Theplantsarekilledbyfireandregeneratefrom seed. Theconservationstatusofthespecieswarrantsinvestigationasitisoflimitedlocaldistribution; itsknownrangeislessthan5kmwiththeplantsconfinedtoironstonesoilswhicharepoorlyreserved (only one small areaexists in ScottRiverNational Park). Etymology. ThespecificepithetisderivedfromtheGreekisos,equal andmorphe, form,referringto the similarmale andfemalespikelets. Acknowledgements We would like to acknowledge the considerable help and kind assistance provided to us by DrLawrie Johnson and Dr Barbara Briggs of the Royal Botanic Gardens, Sydney and to thank ProfessorWalterRossi,UniversityofFlorenceforprovidingtheLatindiagnosis. Wewouldalsolike toacknowledgeMrGregKeighery,SeniorBotanist,DepartmentofConservationandLandManagement, whoseoutstandingresearchintoplantbiogeographyinWesternAustraliahelpedbringtotheattention ofmany botaniststherich anddiversefloraoftheScottRiverregion ofWesternAustralia. 94 NuytsiaVol.9,No. 1 (1993) References Carlquist,S.(1976). Alexgeorgea,abizarrenewgenusofRestionaceaefromWesternAustralia.Austral.J.Bot.24:281-95. Johnson,L.A.S.andBriggs,B.G.(1990).ThespeciesofAlexgeorgea,aWesternAustraliangenusoftheRestionaceae.Austral. Syst. Bot.3:751-8. MeneyK.A.andDixonKW.(1988). Phenology,reproductivebiologyandseeddevelopmentinfourrushandsedgespecies fromWesternAustralia. Austral J.Bot.36:711-26. MeneyK.A.,PateJ.S.andDixonK.W.(1990a). PhenologyofgrowthandresourcedeploymentinAlexgeorgeanitens(Nees) Johnson andBriggs(Restionaceae)- aclonalspeciesfromsouth-westWesternAustralia. Austral.!. Bot.38:543-57. MeneyK.A..PateJ.S.andDixonK.W.(1990b). Comparativemorphology,anatomy,phenologyandreproductivebiologyof Alexgeorgeaspecies(Restionaceae)fromsouth-westWesternAustralia.Austral J.Bot.38:523-41. PateJ.S.,MeneyK.A.andDixonK.W.(1991).Contrastinggrowthandmorphologicalcharacteristicsoffire-sensitive(obligate seeder)andfire-resistant(resprouter)speciesofRestionaceae(S. Hemisphererestiads)fromSouth-WesternAustralia. Austral.J.Bot.39:505-25.