The JapaneseSocietyJapanese Society for Plant Systematics
ISSN1346-7565 Acta Phytotax. Geobot. 59 (2): 97-104 (2008)
0xygyne yamashitae, aNewSpecies of Thismiaceaefrom Yaku Island, Japan
] TETSUKAZU YAHARAiand HIROKAZU TSUKAYA2'
'Department ofBioiogy 1[ticuity ofSciences, 1(}iushu CJhiversiijl 6-10-1 Hakozaki, Higashi-ku, Fukztoka 812-8581, 2'Department .Jdpan; qfBiological Sbiences, Graduate S?rhool ofSlrience, Chiivensity oj'7bkyo, 7-3-i Hbngo, SAtdtional Bundy7o-ku, 7bdyo iI3-O033, Jtrpan; institutefor Basic BiologrJ, IVtitionai institutes ofIVbutural Sciences, to,oclaiji-cho, Okazaki, Aichi 444-8585, .Jtipan
A new species of O-gy?ne O. a saprophytic!mycoheterotrophic specics (Thismiaccac),.vamashitae, from Yaku Island, Kagoshima Prefecture, Japan, is described and Mustratcd, The combination of
characters such as three stamens attached to the perianth and the presence of lamellae at the mouth ofthe perianth tube indicate that it belongs to the genus Ctr)gyne. It is clearly distinct from other known species of Ox.vgyne in having an elliptic hole in the corona, in which stamens are infiexed, and in having threc dichotomous appendages below the stigma. The discovery of O. yamashitae demonstrates that the lowland evergreen fbrest in Yaku Island is a hotspot of endemic plants and worthy to be conservcd.
Keywordsi japan, ([ix.11g:v'ne, saprophyte, Thismiaceae,Yaku lsland
Thismiaceae are a small group of sapro- As in other saprophytic plants, Thismiaceae phytic plants, comprising five genera (Af;rothismia,provide an interesting opportunity fbr studying
Hbplothismia, drygyne, 77iismia and 7Zpuntinia) the evolutien of saprophytes. Most species of
and approximately 50 species (Woodward et aL Thismiaceae, however, occur in the tropics and 2007). Until recently, the family has been treated their populations are very sporadic and difficult as a tribe within the Burmanniaceae (Maas-vanto locate. An exceptional area is Japan where two de Kamer 1998, APG 2003), Recent molecular species of 71hismia and two species of (ixygyne
phylogenetic studies, however, have shown that have been described from several localities with it is sister to Taccaceae, while other members of a warm-temperate climate (Tsukaya in press).
the Burmanniaceae are sister to Dioscoreaceae We here report a third species of(ixMgyne from
(Merckx et al. 2006). This finding implies that Yaku Island, Japan, that appears most similar to saprophytic habits evolved independently in Bur- O, synzatoi (Hatus.) C. Abe & Akasawa native to manniaceae s, stn and Thismiaceae. While some Okinawa Island. The purpose of this paper is to species of Burmanniaceae s. sh: retain photosyn- describe this new species and to provide perspec-
thetic leaves with chlerophyll, all species ofThis- tives fbr further studies.
miaceae are obligatory saprophytes lacking green 'tlssue.
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JuLy 2008 YAHARA & TSUKAYA: A New Oi)g))ne from Japan 99
fiowering individuals of O, yamashitae. Four in- lamella of inner perianth 1 mm long, O.7 mm
dividuals were collected fbr further observation. wide, trapezoid, apex sharply bifurcate, 2-lobed,
In October 2006, the second author, Tsukaya, lobes O.3 mm long. Stamens 3, attached to outer along with Prof. Masatsugu Yokota of Ryukyu perianth; filaments inflexed, with 2 pairs of pro- University, Mr, S, Higa, Mr. K. Shiajo, and Ms. jections at base. Anthers basifixed, pale yellow,
K, Ishii collected O, shinzatoi at its type local- bithecal, introrse, O.5 mm long. Style 1, 1.3 mm ity on Okinawa Island (Kunigami-son, Okinawa long, thiek, ending in 3 short, triangular stignatic
Pref., Ryukyu University Yona Experimental branches, O.25 mm long, O,2 mm wide at base,
Field site, Japan) (Tsukaya et al. 2007, Yokoyama surrounded by 3 dichotomous appendages. Stalk
et al. 2008) and fixed several flowers in alcohol of appendages ca. O.15 mm long, with 2 unequal-
(voucher specimens: H 7lrukaya 061008 [TI], M sized branches elongated opposite each other }lokota s.n. [RYU]). Those materials were used along Tongitudinal axis ofstigma; upper branches to comparc the fioral morphology of O. shinzatoi longer, pointed, ca. O.1 mm in diameter, ca. O,5
and O. vamashitae, mm club-shaped, ca. " long;lowerbranches O,15
mm in diameter, ca. O,15 mm long, Ovacy ca. 1
Results mm long, white. Ovuies many. Llapanese name. Yhku-no-hina-hoshi. Tctronomic description
Atlditional obseivations on O, yamashitae and O. Oxygyne yamashitae Yahara & Tsukaya, sp. nov. shinzatoi
Ox]L{gninae shinzatoi primo aspectu similis, sed stigmati- In appearance, O. yamashitae is similar to bus trifidis, appendicibus majusculis dichotomis differt. O. shinzatoi in having a characteristic star-like 7)pus, JAIIAN, Kagoshima Pref.: along the west- perianth (Fig. 1) ft)rmed by the six perianth lobes. ern branch of Futamata River, Yaku Island, 24 Octeber The lobes are shorter and narrowly triangular in O. 2007, Kengo Fuse, Hiroaki lhmashita & Hiroko Ikecla 2A) and filiform in O. shin2atoi s.n. (holo- FU [in glycerine-alcohol]; iso- TI [in 80% yamctshitae(Fig, atcohel]). (Fig. 2C). At the base of each filiform lobe of O. shinzatoi is a callus-like cluster of round cells Herbs, achlorophyllous, mycoheterotrophic. Roots on the adaxial surface (Fig. 3H). The triangular 1-5, ca. O.5-1 cm long. Stem simple or branched, lobcs of O, yamashitae are smooth. While O. erect, glabrous, less than 1 cm tall, Pcduncle ca. shinzatoi has dark verdigris flowers, the flowers 1 mm in diam. Inflorescence white, racemose, 1 of O. yamashitae are whitish blue. A more defini- or 2(or 3)-flowered, Bracns at base of flowers, 3 tive difTerence between O. Famashitae and O. or more, scale-like, 1 mm long, lanceolate, white. shinzatoi is in the morphology of the pistils; the Flowers in October, upright or inclined, pale blue, stigma is surrounded by 3 rounded appendages grabrous, ca. 5 mm long, 5 mm in diam.; perianth in O. shinzatoi and 3 dichotomous appendages in segments united, 6-lobed, tube campanulate, ca. O. yamashitae (Fig. 2B vs 2D). Additionally, the 3 mm long; perianth lobcs whitish blue, narrowly stigma of O. yamashitae is larger and distinctly triangular, ca, 2 mm long, together appearing star- trichotomeus (Fig. 3D vs 3G), Another distinc- like; perianth lamellae at mouth convex, inflexed, tive feature of O. yamashitae is in the lamellae of united, fOrming an annular corona with a holc the perianth; the lamella of the outer perianth has in center; lamella of outer perianth with hole in an elliptic hole in which a stamen is bent inward which a stamen is bent inward toward the stigma; toward the stigma (Fig. 3E), In O. shinzatoi, the
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July 2008 YAHARA & TSUKAYA: A New (]t)igyne from Japan 101
lamellae of the perianth are free (Fig. 3H). The All three Japanese species, including O. yamashi- elliptic hole of O, yamashitae is interpreted as be- tae have blue or green, cup-shaped fiowers, while
ing the result of fusion of the lamellae. The free O. triandua has deep brown, bell-shaped flowers lamellae of O. shinzatoi have very low teeth (Fig.(Schlechter 1906). It is highly probable that thc 3H) but the lamellae of the inner perianth of O. three Japanese species are closely related. yamashitae are deeply bilobed (Fig, 3E), The ba- While the overall morphology and the flower sal part ofa the filament has two pairs ofprojec- color of O, vvamashitae resemble the other two tiens, one being larger (Fig 3F). species from Japan, O. yamashitae is clearly distinct from O. shinzatoi, as described above. Discussion 0xlygyne yamashitae is also distinct from O. byo-
dbi based on the clearly illustrated fioral features
systematicposition and cfistinctness published with the figures associated with the Among the five genera of Thismiaceae original description (Abe & Akasawa 1989). ()xy- (afrothismia, Haplothismia, Orygyne, 7:hismia gyne hyodoi is similar to O. yamashitae in having and 7ipuntinia), Hoplothismia and (]xyglyne are all lamellae of the perianth fused to fbrrn an an-
characterized by having filamentous stamens with nular corona with a central hole at the mouth of
filaments basally broadened, attached to the mid- the perianth tube. (ixygyneyamashitae has a more vein at the base of the perianth lobes, and curving specialized corona having three narrow holes in inward at the apex to panially obstruct the mouth which staminal filaments are inflexed (Fig. 3B, E). of the floral tube (Heywood 1978, Woodward et Second, O. lo?odbi has three clavate appendages aL 2007). In stamen morphology, Haplothismia below the stigma, but O. yamashitae has three and C]trygyne are similar to Tltccaceae, with which unequally dichotomous appendages (Fig. 3C, D). Thismiaceae are related (Merckx et al. 2006). Thirdly, filaments of O, byodoi are simple at the Other genera of Thism{aceae have more reduced base, but those of O. yamashitae are broadened andfor specialized filaments and are probably and toothed at the base (Fig. 3F), From thosc more derived. A recent molecular phylogenetic morphological ebservations, it remains uncertain study also showed that ([ixygyne is relatively basal whether O. yamashitae is sister to either of the within Thismiaceae (Ybkoyama et al. 2008). Ory- other two species. Molecular phylogenetic stud- gyne is, however, derived in having three stamens ies are needed to elucidate the relationship among while all other genera including Haplothismia the three Japanese species. have six stamens (Abe & Akasawa 1989, Wood- A key to the species of thygyne is provided ward et al. 2007). drygyne. yamashitae has three below,
stamens and the stamen morphology is identical A1. Flowers bel1-shaped, brown ...... O. triandra with other species ofthe genus, A2. Flowers cup-shaped, verdigris, emerald green, or Oaygyne triandra Schltr., the first species whitishblue...... ,.,,,,.,.....,...... ,...... B
described in the genus is in tropical forests ofMt, BI, Perianth lobes filifbrm; base ef lobes with callus-
like cluster of round cells on adaxial surface; inner Cameroon in West Africa (Schlechter 1906). The with free tamellae at mouth ofperianth tube; second species described, as Saionia shinzatoi perianth outer perianth lacking lame]lae; pistil with 3 rounded (Hatusima 1976), from Okinawa Island, Japan, appendages belew stigma; filarnents simple at base; was in (]xygyne by Abe & Akasawa (1989) placed fiowers verdigris .,,...... ,,...... ,,,, O, shinzatoi a third O. C. when they described species, byodoi B2, Perianth lobes narrowly triangular; base of lobes Abe & Akasawa, from Ehime Prefecture, Japan, smooth; inner and outer perianth lamellae fused
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c B ,B' pt--in(e-? dilmrrn N D t,t st TTtEVfimm e-.3mm
. zrE"rsrm
-O.6 E mm I .O rr"n
FIG. 3. Comparison of Q]rygyneyamashitae and O. shinzatoi. A to F: O. yamashitae. G and H: O. shinzatoi. A and A': whole plant, B: front (B) and Iateral {B') vicw ofperianth tube and subtending bracts. C and D: stigrna. E] perianth lobes, perianth larnellae, and a stamen viewed from inside of the corolla tube in O, yamashitae, F: two inner perianth lobes with stamens and a lamella ofan outer perianth efO. yamashitae. The fused lamella was splitted at thejunction (shown by wavy Lines). G: Stigrna. H/ perianth lobes, perianth lamelLae and a stamen viewed from inside of the perianth tube ofO. shinzatoi.
to form an annular structure with central hole at Ecoiogy and Conservation
mouth...... ,,,,,...... C Although the flowers of O. yamashitae are C1. Perianth lamellae equal in size at mouth, fbrming whitish blue, they are extremely inconspicuous in annular structure called annular taenia; stamens bent the forest, Most fiowers we observed in the field inward to central hole; pistil with 3 clavate append- were hidden among fa11en leaves; the entire flow- ages below stigma; filaments simple at base; flowers er was visible only after the were emerald-green ...... ,...... O. dyodoi fa11enleaves C2, Perianth lamellae unequal in size,, fused with each removed (Fig. IB). The flowers had neither rec- fbrm an annular structure; 3 lamcllae of in- other to ognizable nectar nor recognizable odor, We ob- ner perianth larger, with 3 holes in which stamens are served mites (Fig. IA) and ants rarely visiting the bent inward; pistil with 3 three unequally dichoto- flowers, but they showed no interest in the pollen. mous appendages below stigma; filaments toothed at The flowers of O. yan7ashitae appear to be self base; fiowers whitish blue , , . , . . , , , . , , , , , O. yamashitae
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fertilizing, irrespective of its highly specialized Pempectivesforjuture reseanrh
spatial arrangement of stamens and stigma. Although Japanese species of ( trygyne pro- The two populations of O, yamashitae dis- vide an interesting opportunity for studying the
covered by Mr. Yamashita are on the lower south- evolution of achlorophyllous mycoheterotrophic
ern slopes of Yaku Island in humid evergreen plants, the populations are extremely difflcult
broad-leaved forests near streams, Unfbrtunately, to find. In 2004, O. shinzatoi, which had not
the habitat of the first population at YUdomar{, been colle ¢ ted since it was described (Hatusima at an elevation of approximately 180 m, was 1976), was rediscovered at the type locality. The
destroyed by the construction of a fbrest road, rediscovery triggered a series ef studies, includ-
Lowland evergreen fbrests remain in the vicin- ing a cytological study (Tsukaya et al. 2007), ity of the first population, along a stream below a molecular phylogenetic study (YOkoyama et Mt. Hasa. We expect that additional populations aL 2008) and a molecular phylogenetic study of remain. Because the second population along the fungi associated with the roots of O, shinzatoi. Futamata River occurs at 390 m, further effbrts to The discevery of O. yamashitae has enriched our
find O, yamashitae between 200 and 400 m at the opportunity fbr elucidating the evolutionary his-
foot ofMt. Hasa should be undertaken. tory of exygyne, Studies using cytological and
At low altitude on the southern slope ofYaku molecular phylogenetic techniques are now in Island, humid evergreen fbrests occur along Tain- progress. Further, more in-depth studies using in
okoh River, Futamata River, Suzunokoh River, vitro culture and genomic analysis might help us
Yugo River and other smaller streams between to understand the mechanisms behind the evolu-
those rivers. Two endemic ferns, PteFis havL'abataetion ofmycoheterotrophic p]ants in general. Sa. Kurata and Linctsaea kawabatae Sa. Kurata ,
are restricted to humid fbrests in that area, Aster We express our deepest thanks to Mr. Hiroaki Yama-
shita who discovered O. and us an yakushimensis (Kitam,) Soejima & Yahara and yamashitae provided extraordinary opportunity fbr studying this interesting Pertya yakushimensis H. Koyama & Nagam. are plant. We also thank Mr. Kengo Fuse who helped us also restricted to that area, inhabiting forest mar- to find plants of O. yamashitae at the type locality, and along streams, The discovery of O, gins yainashi- Ybichi Arata, Ichiro Makise, Kenshi Tetuka and other
tae has provides additional evidence that the low- members of the Yakushima Overall Conserving Asso-
land evergreen forests in this area are a hotspot of ciation who invited Yaliara to the YOCA meeting on 8
October 2006 where he was shewn the of O. endemic plants. Unfortunately, only a part ofthe photograph yamashitae by Mr. Yamashita. area is preserved. On Yaku lsland, 38,415 ha (76% of the 50,455 ha) is managed as a National Forest, References 20,989ha (61%) is preserved as a National Park, and 1O,747 ha (2 1%) is registered as a World Nat- Abe, C, & Y Akasawa. 1989. A new species of Ory- ural Heritage site. The Futarnata River population gyne (Burmanniaceae) fbund in Shikoku, Japan, J, of O. is located within the National yamashitae Jap. Bot. 64: 161-164, Forest area the National Park butoutside of and APG (Angiosperm Phylogeny Group), 2003. An update the World Natural Heritage area. Tb conserve 0. of the Angiosperm Phylogeny Group classification
fbr the orders and families of flowering yamashitae and other endemic species restricted plants: APGII, Bot J, Linn, Soc, 141: 399-436, to the lower altitude ofthe southern slope ofYaku Hatusima, S. 1976. Two new species ofBurmanniaceae Island, fUrther plans fbr restricting forest logging from Japan. J. Geobot. 24i 2-6. and construction are needed.
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104 Acta Phytotax. Geobot. Vbl. 59
Heywood, V. H. 1978. Flowering Plants of the Wbrld, Tsukaya, H., M. Ybkota & H. Okada. 2007, Chromo- Croom Helm, London. some charactcristics of thygyne shinzatoi (Bur- Maas-van de Kamer H, 1998. Burmaniaceae. Ih: Ku- manniaceae) and its phylogenetic significance. bitzki, K., H. Huber, R J, Rudall, P, S. Stevens & T. Acta Phytotax. Geobot. 58(2!3): 1 OO-106,
and Stutzel(eds,),The Families Generaof Vascu- WOodward C. L. , P.E. Berry,H. Maas-van de Kamer lar Plants, vol, III, Monocotyledons: Li]ianae (Ex- & K. Swing. 2007. 7iputinia foetido, a new myco- cept Orchidaceae), pp, 154-163. Springer-Verlag, heterotrophic genus ofThismiaceae from Amazo- Berlin. nian Ecuador, and a likely case of deceit pollina-
Merckx V., P. Schols, H. Maas-van der Kramer, P. tion, 1laxon 56: 157-162.
Maas, S, Huysman & K. Smets, 2006. Phylogeny Yahara, T., H. Ohba, J. Murata & K. Iwatsuki. 1987. and evolution of Burmanniaceae (Dioscoreales) Taxonomic review of vascular plants endemic to based on nuclear and mitochondrial data. Amer. J. Yleikushima Island, Japan. J, Fac, Sci, Univ. Tokyo Bot. 93: 1684-1698. Sect, III, 14: 69-119.
Schlechter, R. 1906. Burmanniaceae afi-icanae. Bot. Ybkoyama, J., YL Koizumi, M. YOkota & H. Tsukaya.
Jahrb. Syst. 38: 137-143, 2008. Phylogenetic position of Oxlygyne shinzatoi Tsukaya, H. Burmanniaceae, in: Iwatsuki K., D. E. (Burmanniaceae) inferred from 18S rDNA se- Bouffbrd & H. ehba (eds.), Flora ofJapan 4b, Ko- quences. J. Pl. Res. 121: 27-32. dansha, Tbkyo. (in press)
ReceivedIVbvember 20, 2007; accqpted ILdby 6, 2008
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