VNU .j O U R\'A í o r S C IE N C E , Nal S ã - & T ech XIX, N ại 2003 CLEISOSTOMA FLAVESCENS- N E \ V O R C H I D S P E C 1U S F R O M N O R T H E R N V IE T N A M Lcơnid V A vervanov & A nna L A veryanova K o m u r o v B o t a m c a ! I n n t i t u t e , R u s s i a n A c a d v m v oỊ S c i e n c e % Abstract C ỉc iso sta m a ỷlavesccĩis Aucr c&A c ry a n o v ữ (O rc h id a cea e) di&couercd in l i m c s t o m a r c a of' th e n n rth ern V ic tn a m is d e s rr ib c c ỉ a s ct ÌXỸ.UỈ apccitìs to scienac ỉt ỈHĩlongs to accĩ C le iso sto m a a n d ha* cìoac rclation to Cleisostoma a s p c r s u m ('Rvhb.Ị.) G n r a y a n d c discolor L iĩtd ì R eccnt boLanical explorations of lim estone areas in th e northern V ieinam outlined this region as a vcry important center of plant cndemism rtch in orchid spccies having very limitecỉ distribntion Tlìis rocky mountain arca composccl vviih ancicnt liighly crodecl Paleo/.nic and carly Mesozoic limestuno hold unique botanical refugium for numerous outatanding strictlv enđcmit: orchids Atnong thcm such exciting rccently A n o e c io c h iỉu s discovercd ca ỉca re u s, sp ecies H o lco g lo ssu m having grcat W(iĩiỵii> horticultural P a p h io p e d ilu m potential h a n g ta n u m as , p h c l e n a e , p h e n r y a n u m , p h e r r m a n n i i , p h i e p i i , p t r a n l i e n i a n u m , p u ic tn a m c n s e and many uthcrs (Averyanov, 1997, 1998, 2000 2002 a,b; Avcryanov, Averyanova, 2000; Averyanov, at al., 2000, 2001; Avervnnov, Rice, 2002) Group of ỉhcse orchid spocics inrludes also nevvlv discovercd yellovvflowering species of the gcmis C l e i s o s l o m a Blumo - C t c i s o s ỉ o r n a flave$ccĩU f, \vhich represcnts new spet:ies for scionce This orchid has dosc relation to C lc i s o s t o r n a a s p c r s u m (Kc:hb.f.) Garay and c d i s c n ỉ o r Lindl It was foimd in the northern Vietnnm during field vvorks un dcscription of vegotation in habitats of endomic Victnamesc Paphiopeclilums Description of this rare probablỵ cndemic plant is prescnted l)«low R e n a n th e r a c itrin a , R v ic tn a m e n sis C le is o s to m a íla v e s c e n s Aver & Averyanova, s p n o v (C l e i s o s t o m a sect C ỉ e i s o s t o m a ) Tvpe: Northern Victnam, Tuycn Quang Provin.ce, Níi Hang Dislrict, Xuan Tam Municipality, ncar Ban Cai villagc (22°29*N, 105°20'E) Primnry brnndleavcd cvergrecn dry ĩorcst on very steep slopes of highly erodcd rem n a n t limestonc ridge at clev 450-500 m a.s.l Commoxi epiphvte 22 March 2001, P K ỉéOc, N x T a m , ỉ, A v c r y u n a v , H A L (holotvpc: HN!; isotype: i-K!) Fig A sp c c te b u s p r o x im is (C le is o sto m a a s p e r s u m ( R c h b Ị ) G a r u y c.t c d i s c o l o r L i n d l ) s p c c i c s J10 Ĩ'CI Ị o l i o r u m (ip ic e b i l o b a t o r o t u n d a t o - o b t u s o , Ị ĩ o r i b u s m i n o r i b u s fla v ìs c e n tib u s t la b e ỉỉi s tr u c tu r a vt lỉỉ p o s te r io r i f o r m a v a ỉd e d iffc rt vvith roots about mm vvidc, covered throughout with gray or whitifih satiny vnlamen S t e m ascendant, subercct, curved at the basc, rigid, about E p ip h y te L c o n id V A v c r y a n o v A n n a L A v e r y a n io v m >ava 4*C(12) cm long, mm in diam., internocỉes about 0.7 cm long L e a v e s usuallv S - 8.-8 dorsiventral, coriaceous, up to 20 cm long and 2.1 cm wide, conduplicate w/itththth distinct, prominent median vein, unequally bilobulate at the apex, vvith brcoíadidad obtuse asymmetric lobes l n f ỉ o r e s c e n c e s lateral, 11-14(16) cm long, branched, scraỊpepepe and rachis thin, rigid, tvvig-like, deep green vvith purple or purple-violet tiimt.it nt ỉ n ị ĩ o r e s c e n c e b r a c t s ovate, about mm long and 1.5 mm wide F ỉ o w e r b r a c t s srma.ll.ll.ill ovate, about mm long and o.õ mm vvide P e d ic e ì a n d o v a r y 3-5 mm long, to im mrmm wide F l o w e r s odorless, tepals and lip light dull yellovv, side lobes and apex of tlhchche lip white, cơlumn yellowish-white, anther cup dull yellow with few small purrp>lolo)le marks near the apex; ovary dull yellovvish-green with light inđistinct purple tũ n t itnt Dorsal sepal and petals curved forward, tepals except lip with indistinct purpili sbshsh median veins S e p a l s obovate, about 3.8 mm long and 2.1 mm wide P e t a l s narro'\v lyly/ly ovate, about mm long and 1.5 mm wide L i p about mm from tip of mid-lobíe tctc to apex of spur S p u r cylindrical, slightly flattened from lateral siđes, more or llespssiss straight, about mm long and 1.4 mm at the widened base, the back-vvall cailluiUHus triangular in sagittal section, with two distal narrovving horns S i d e lo b e s recunved djd, broadlv truncate, Tinely denticulate at the eciges M i d - l o b e fleshy, short., obtmse>eseacuminate, almost at right angle to the spur C o l u m n about, l.õ mm high A m t k e ì e n e r c u p hemispherical, at íront attenuate, dull light yellowish, vvith small indist;incicnct purplish marks P o l l i n i a sub-equal, in two pairs E tim o lo g y : The name reílects dull pale-yellovv color of flowers N o t e C l e ỉ s o s t o m a P a v e s c e n s may be related to C l e i s o s t o n i a a s p e r s u m (Rchib.r f .f.) Garay and c d i s c o l o r Lindl., but distinguished by having broadly obtuse apical lea)aeaf lobes, in distinctly smaller dull pale yellowish flowers and in form of back- wa]al all callus in the spur This species vvas observecỉ as locallv common epiphyte in prinnanniry broad-leaved evergreen dry forest on verv steep slopes of highly eroded reminan m n t limestone ridge at elevation 450-500 m a.s.l It flowered under cultivatiom iìiỉ in December-January The species is local endemic of the northern Vietnam prob)abl-)l'jDly associated in its distribution with area of P a p h i o p e d i l u m h a n g i a n u m / p p t r a n l i e n i a n u m and p v i e t n a m e n s e (Fig lj) A ck n o w le d g m en ts Tho species was discovercd during botanical explor.atioioiion expedition according to grant program of 100% F u n d F a u n a & F l o r a I n te r n a tìio r ìG ia ia l (grant "The distribution of P a p h io p c d ilu r r ì v i e t n a m e n s e and its current status im th hche wild") We also vvoulđ like to thank Mr A.Sennikov for his kind correction o»f 0U)UDur use of the Latin language and Prof Phan Ke Loc for final editing of the paper iưi thhche format of Vietnamese edition Cleisostorna F l a v c s c e n s - Neit' O r c h i d Fig C l e i s o s t o m a p a v e s c e n s Aver & Averyanova flo w c rin g p la n t; b- flo w e r w iih flattcned sepals and pctals; c- flo w c r, side view ; t - flo w c r, side v ic w , w ith s a g itta l section o f thc lip ; e - lip w ith cu t o f m id -lo b e ; f- lip , lack vievv; g - hack-wall callus, siđe vicw; h- anlher cup (o p e rc u lu m ), vievv 1‘rom above; p o llin a riu m , Iro n ia l and sidc v ic w s ; j- lo ca tio n o f alone disco vcre d p o pu la lio n I)ra w n rom thc lypc 4 Lconỉd V Avctyanov & Anna L Avcrycimioovoiiova Reíerence Averyanov, L.v., R e n a n t h e r a c i t r i n a A new yellow-flowered species fronn ttbtl the limcstone areas of the northern Vietnam O r c h i d s - M a g A m e r O r c h S o tc *6