Botanical Studies (2010) 51: 99-106. SYstematics Two new species of Hypodematium (Hypodematiaceae) from limestone areas in Guangdong, China Fa-Guo WANG, Dong-Ming LIU, and Fu-Wu XING* South China Botanical Garden, Chinese Academy of Sciences, 723 Xingke Road, Tianhe District, Guangzhou 510650, P.R. China (ReceivedJune25,2008;AcceptedJune18,2009) ABSTRACT. Hypodematium humile F. G. Wang & F. W. Xing and H. villosum F. G. Wang & F. W. Xing, two new species of Hypodematiaceae from Guangdong, southern China, are described and illustrated. Their sporemorphology,ecologyandconservationstatusarealsopresented.Hypodematium villosumdiffersfromH. fordiiinhavingglabrouspetioleexceptonthebase,bothsurfacesoflamina,rachisandcostadenselycovered withlongacicularhairsca.1mmlong,andapexofpinnuletsacute.Hypodematium humile differsfromH. glandulosuminhavingleaves8-11cmlongwithbothsurfacesoflamina,rachisandcostasparselycovered withrod-shapedglandularhairsandcaducousindusium.AkeytothespeciesofHypodematium knownfrom Guangdong Province is provided. The systematic relationship of HypodematiumwithLeucostegiaisalso discussed. Keywords: China; Endemism; Guangdong; Hypodematium humile; Hypodematium villosum; Limestone; New species;Rareplant;Sporemorphology. INTRODUCTION MATERIAL AND METHODS Described in 1833, Hypodematium Kunze is the Herbariummaterialsformorphologicalstudywere onlygenusoftheHypodematiaceae.Iwatsuki(1964) obtainedfromPE,IBSCandSYS.Sometaxawerestudied reviewedthegenusandrecognizedfourspeciesincluding during our field-trios expeditions to Guangdong in 2005 one subspecies. More recently, over 18 species of and2008.FortheSEMstudies,sporeswereplacedon Hypodematium,mainlydistributedinsubtropicaland aluminumstubswithdouble-sidedtapeandsputter-coated temperateareasofAsiaandAfrica,havebeendescribed withgold.Sporeswereobservedandphotographedunder (Shingetal.,1999;TsaiandShieh,1994).China,with14 aHitachiJSM-6360LVscanningelectronmicroscope. speciesandonevarietyofHypodematium, isregardedas Morphologicalobservationsandmeasurementson thecenterofdistributionofthisgenus.Hypodematium collectionsweremadewitharulerorbinocularlight isauniqueferngenus,becauseitgrowsonsoilsderived microscope fitted with an eyepiece graticule. Only mature fromlimestonerocksandhasdistinctiveswollenscaly plantpartsweremeasured.Detailsofplantgrowthhabit baseofstipeandindusium.Hypodematiumisclosely andsize,colouroffreshleavesandscales,andinformation relatedtoCystopterisandsomeauthorsconsiderittobe onthehabitatandlocalityweretakenfromthecollector’ adistinctsectionofthis(Ching,1935).Duetoitsunique s notes recorded on the herbarium label and from our field morphology(Iwatsuki,1964),Hypodematium hasbeen observations. placedindifferentsupragenerictaxa,e.g.Athyriaceae Thematuresporeswereputinacentrifugetube,70% (Woodsiaceae),Dryopteridaceae,andThelypteridaceae. ethanolwasadded,andsporesshakenwithanultrasonic During a field-trip to the limestone area of Guangdong wavebathfor10min. After4mininanEppendorf Province(southernChina),wecollectedsomespecimens centrifuge,theywerethricewashedwith70%ethanol ofHypodematiumthatwewereunabletoassigntoany andthriceshakenwithanultrasonicwavebathfor10min ofthepreviouslydescribedtaxa.Thus,theyaredescribed afteraliquidexchangeeachtime.Finally,thesporesand hereastwonewspecies. ethanolweremovedtodouble-sidedadhesivetapewith Eppendorf. Theywerethentreatedbydessicationand *Correspondingauthor:E-mail:[email protected];Tel: spray-goldwhenethanolvolatilized,andSEMwasusedto +86-20-37252557;Fax:+86-20-37252831. studytheirmicrostructure. 100 Botanical Studies, Vol. 51, 2010 NEW SPECIES obtectis, pinnis 12-15-jugatis, lobis acutis, margine villis acicularibus densis obtectis. Affinis H. microlepioidi, sed 1. Hypodematium villosum F. G. Wang & F. W. Xing, sp. lamina quadripinnata, petiolo pinnae ca. 1.5 cm longo, nov. —TYPE: CHINA. Guangdong Province: Meizhou lobis acutis integris, pinnis utrinque sine squamis differt. City, Jiaoling County, Xingfu Town, Changlong Village, Plantsslender,50-65cmtall;rhizomesshort-creeping, limestone mountain, altitude 50 m, 15 Nov 2005, Faguo coveredwithscales;scalesreddish-brown,narrowly 毛葉腫足蕨 Wang et al. 1251.(Holotype:IBSC). lanceolate,0.6-1cmlong,ca.1mmbroadnearthebase, Figure1 membranaceous, lucid.Leavesclosetogether;petiole Species affinis H. fordii, sed petiolo praeter basim 25-30 cm long, ca. 1 mmin diameter,stramineous, glabro, lamina 25-30 cm longa basi 35-40 cm lata, coveredwithscalesthesametotherhizome,glabrous lamina utrinque, rhachi et costa villis acicularibus densis upward;lamina25-30cmlong,base35-40cmbroad, Figure 1. Hypodematium villosum F. G. Wang & F. W. Xing. A, Habit; B, Rhizome and lower portion of petiole; C, Abaxial view of portionofpinnulerachiswithpinnulet;D,Adaxialviewofportionofpinnulerachiswithpinnulet;E,Scalefromrhizome;F,Hairfrom lamina; G, Sori; H, Sporangia. Drawn from Wang Faguo et al. 1251 (IBSC). WANG et al. — Two new species of Hypodematium 101 ovate-quinquangular,apexacuminateandpinnatifid, pairsoppositeandenlarged,ca.4cmlong,basedecurrent quadripinnate,tripinnateupward;pinnae12-15pairs,basal withnarrowwing,pinnate;thirdpinnulesca.6pairs,apex twopairssub-opposite,alternateupward,oblique,first acute,basedecurrent,marginlobedto1/2;pinnulets3-4 basiscopicpairenlarged,5-6cmapartfromupperone, pairs,apexacute,entire,margindenselycoveredwithlong 16-20cmlong,6-8cmbroadatthebase,triangular-ovate, acicularhairs;veinsprominentabaxially,veinletsimple, apexacuminate,withpetioleca.1.5cmlong,tripinnate; 1-2oneachlobes,endinginmargin.Laminapapyraceous, pinnulesca.12pairs,alternate,anadromous,oblique, virescentwhendry,denselycoveredwithgraylong closetogether,basiscopicpinnulebiggerthanacroscopic acicularhairsca.1mmlong,especiallyontherachisand ones; secondary pinnules 8-10 pairs, alternate, first basal costa.Sorismall,dorsiferousonthemiddleofveinlet, Figure 2. SEMphotographsofHypodematium spores.A-B,Hypodematium villosum(sporefromF. G. Wang 1251.A,×1,500,scale bar 10 μm; B, ×6,000, scale bar 2 μm); C-D, Hypodematium humile(sporefromF. G. Wang 1255. C, ×1,600, scale bar 10 μm; D, × 8,500, Scale bar 2 μm); E-F, Leucostegia immersa (Spore from J. S. Xin 626 (PE), E, ×1,800, scale bar 10 μm; F, ×5,000, scale bar 5 μm). 102 Botanical Studies, Vol. 51, 2010 oneoneachlobe;indusiumroundednephroid,grayish, Conservation status. Hypodematium villosumisonly membranaceous,denselycoveredwithlongacicularhairs, knowninasinglelocalityandhasaverysmallpopulation persistent;sporemonolete,perisporepsilate,withsome size.Therefore,ithasaCriticallyEndangered(CR) granularornamentation. designation according to the IUCN (2001). Ecology.Hypodematium villosumisacalcicolousfern Etymology. Named from the Latin word ‘villosum’, thatattachstorockytunnelsonlimestonemountainin referringtothelongacicularhairsonthelaminathat FungShuiWoodnearavillage.Plantswerecollected distinguishotherspeciesofHypodematium exceptH. inassociationwithCtenitopsis devexa (KunzeexMett.) microlepioides. Ching & Chu H. Wang, Pteris plumbeaH.Christ,P. Spore morphology.Lightmicroscopeobservation deltodonBaker,Pterolobium punctatumHemsl.,and showedthesporeofHypodematiumiseudipleuraland Alocasia macrorrhizaSchott. monolete,andthecorrugationoftheperisporeisstriate, Distribution. Hypodematium villosumisendemicto reticulateorcircinate(Zhangetal.,1976).Scanning Changlong village, Xingfu Town, Jiaoling County, eastern electronmicroscopeobservationfoundthesporeof Guangdong, southern China (Figure 4). Hypodematium villosumtobemonoleteandtheperispore psilatewithsomegranularornamentation(Figure2). Figure 3. Hypodematium humile F. G. Wang & F. W. Xing. A, Habit; B, Abaxial view of portion of pinnule rachis with pinnulet; C, Glandular hair from lamina; D, Sori; E, Sporangia; F, Scale from rhizome. Drawn from Wang Faguo et al. 1255 (IBSC). WANG et al. — Two new species of Hypodematium 103 Figure 4.DistributionofHypodematium villosum(blacksquare)andH. humile (black triangle) in Guangdong, China. (from Yan, 2004). However,theperisporesoftherelatedspeciesH. fordii differsprimarilyasfollows:petioleglabrousexceptthe andH. microlepioidesarecircinateandstriate,respectively base,lamina25-30cmlong,base35-40cmwide,surfaces (Zhangetal.,1976). oflamina,rachisandcostadenselycoveredwithlong Sporesurfaceisunclearlyobservedofcontaminated acicularhairsca.1mmlong;pinna12-15pairs;apexof smallsporescollectedfromherbariumspecimens.After pinnuletsacute,margindenselycoveredwithlongacicular beingsoakedin70%ethanolandshakenintheultrasonic hairs,andperisporepsilate. wavebath,thetreatedsporesurfacebecomesclearerthan Hypodematium villosum a l s o r e s e m b l e s H. untreatedonesunderSEM.Thismethodiseasytocarry microlepioides (Shingetal.,1999),aplantendemicto outandobviouslymoreeffectivethanroutineprocedures. YunnanProvinceinChina.Bothspecieshaveglabrous Morphological notes. Hypodematium villosum canbe petiole,andtherachisandcostaofbotharedensely differentiatedfromotherspeciesofHypodematiumbyits coveredwithlong,grayishacicularhairs.However, slenderindividualplants,longacicularhairsandsmallsori thelatterdiffersfromH. villosuminhavingthelamina onthelamina.ItresemblesH. fordii (Shingetal.,1999), 3-pinnate;thepinnulesessile;thepinnuletoblong,and which is distributed in Guangdong, Guangxi, Fujian, and theapexwith2-4teeth;bothsurfacesofpinnahave AnhuiProvincesofChinaandJapan,althoughH. villosum rufousandnarrowlylanceolatescales. Amorphological plantshaveamoreslendertexture.However,theformer comparisonbetweenHypodematium villosum, H. fordii Table 1.DiagnosticcharactersamongHypodematium villosum, H. fordiiandH. crenatum.