The Genus Callitriche (Callitrichaceae) in Asia Richard V. La7nsdown45 The Bridle, Stroiud, (Glos, 1,5 4SQ, Unilted Kingdom. rlansd(ownIvCartleola.ilemon.co.tukA\isr l't '. 'axonomic review is provided for Coali-lriche laxia ccurring in central aiin eastern Asia eastofll the U rals and in soulheaslern \sia north of IrianJava llarat. Th''re(e Inw species: Ca(litriche./iI cicar/)i.,(. gltrecost, and C. ratrnionr are delscribed frontNepal, Bhutan, and T'aiwan, China. respectively. Two.new vartilies are also described: Callitrichlc paluslris1. . var. ni'goalaa fro Siberia in Riussia and Calli-ricrue pa(lustris I. var. ,strumos [ from western Suniatrain lndonesia. C(llitrilch naun is newly referred asa synonymll (l C. jalipoica frngelniann ex I legelmnaier.Callitriche oriyzAtornit Petrov is transferred andreduced in rank to a variety of (,'. palustr/is I.. Calli-riche wighlion \\ allich i \ in ighl is lectotypifiedl. Key ,cdls: Asia, Calliirichec, (allilrichaceae. Ca('l/ilricl' I.. is a genus oif mnomecious. or in a single case (C. petrici R. Mason sul)slp. petri'ci), (ioeciou ans, Pl wil with lowers tlat are axillary uand iisuallV solitarv )ill that mas occur in various but a subtendling pfair of bIracts may he present in soni( slpecies. The Ifruits are( sctlizocrps, separating into four i(e'ricar)ps, which are dry. winged or not, with wings from the inner frulit layer. The taxonomy and identification of Callilriche species are dependentl almost entirely ol n reproductive fteatures, althoughl oc((casionally other details such as venalio()ll and leal shape may also be useful. In preparing thle treatmiientll ofl Callitricihe for the tnglish version of Ile Flora of (China series, herbarium speinen('s were studied fro'i al area ill Asia extenling from Ililt Irals Ieiast to Kaicihatka Slan I'ssnriland in the IRussian Ealr Iast and south to so)ilhern Ilndonesia but excluding the eastern province of Irian Jaya Haral. Populations I'romn here and Papua New G(uinea were excludled as they appear to have" closer alfinities willt Australasian laxa of' the genus (Merrill & I'erry, 1941: Scholsmlan. 1985). Thliree inew\v species were identified: Callitriclhiihscicra7rp occurring in the IHinmalayas, fronm Iliathrough Nepal to southern (China; (C. glar'eoslrepresentled by)v single specimens from Ihlllan andTilbet; anil C. raeniati applarently onlI occurring inl'I'aiwan. Callitriche pl.ustris L,. was found to showsltrong variation, wilh etxrenlts Ibeing descriled as var.ne'galatl fronll Kamcialtka in Rlussia, var. s:ltricillSfrom islands in southeastern Asia. and var. orvze-lorini,. formerly described as C. or-a'btorrutn Petrov.from sou11 lthern (China. Japan. 1and Taiwan. Few accounts of the genus in Asia gi\e dueconsideration Io reproductive I'ealllres and conse-quently there is munch niisidentification. Manyaccounts reportl Callitriche staignalis Sco)poli IfroniAsia (iCheng & Ming. 980;( Kak & Javeid, 1982:Cook. 1996; Sarwar. 1998: Larsen. 2000). whlile Kakanli Jal id (i1982) also reportIl C. ob/tuslranula iLe all1and (1 . iriiincl llI IliussoIn . I However, ltoroughl review ofherbarinum nmaterial (Scholsnian. 1985: Lansdown,200,() in piress) has failed to find anl material ofl C.st'analis east of lhe lUrlals. C(. obltsonguil ila eiast of theMedilerranean, or C. truncat' east of tilhe Black Sea.When possible, I have taken the literalure intoaccouniil in preparing this revision. I lowever, problhemswith Ipotenttial misidentlilifcation mean thai the liera-ture has mainly been usled to clarify elements ofdistribulioln. The informal ion employed to prepare this revisionderives fromn review of more than 100 specimens inBM. C(;E. . HAST. HI111. K. i I T.I. M MIC MO(. P.PI, PPil TAI TNM, and(I TNU. All descrilptive andbionmeri data employed here are blased on herl)ariumspecimens collected in Asia. except for Illose relalingto C. polustris var. pIallusiris. The list of materialstudiedl indicales Ihe number of specimens seen;however. where data were colleclrd fronl onl\ a smallnumber of spe)'ime'ns., this is slated. I have provid~ed illustralions of the fruits of eachtaxon xcrept where these are already available in theliterature. I ha\e provided a key to lte idenliflicalionof all laxa kltnown occur in ihe region, although onlynovellies are considered ill lthe text.Ki.' IOn l'P I; (ut I. I7.I' :w;/ S|I:II':, VFo! )xN i \ Asi \la. I ils gIlinglil ..................I l). Irails c .tle rl winged ......... . ....... . . 52a. IBr cts lacking .............. C. pepl/oid' .s uIllall21). r;icts prescnt . .. .. .. ... .. .. . .. .. . .. .. .. . 33a. All leaves linigulalc with onlv a single ein; lbracts callurotIus . . . . . . . . . . . . . . .... C. s ( inci'ps PeI'triv;31). Soime or all leaves 'expa lded. I-In tmant-vined; ]iraels persisltent . . . . . . . . . . . . . . . . . . . . . . . . .la. Iha'tls as long anld wide as ripe fruit; lea v'enation sitm ple ... ................ ........... .... .C. pali.stris I.. \ar. iortetorlum (Pl'tro\ ) Ians.i lownNOVON 16: 354-361. Pt liSItIi) ON 7 Nov:MIi.;t 2006.
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