Bull. Natl. Mus. Nat. Sci., Ser. B, 46(2), pp. 75–87, May 22, 2020

New Localities of Seed Plants Recorded from the Subtropical Ryukyus
of Japan at Island Level Based on Herbarium Data
Goro Kokubugata1, *, Atsushi Ebihara1, Yukiko Saito2, Masaharu Amano3, Atsushi Abe3,
Koh Nakamura4, Akiyo Naiki5, Tadashi Kajita5 and Masatsugu Yokota6
1

Department of Botany, National Museum of Nature and Science,
4–1–1 Amakubo, Tsukuba, Ibaraki 305–0005, Japan2
Department of Science Education, Faculty of Education, University of the Ryukyus,
Nishihara, Okinawa 903–0213, Japan
3
Okinawa Churashima Research Center, Okinawa Churashima Foundation,
888 Ishikawa, Motobu, Okinawa 905–0206, Japan
4
Botanic Garden, Field Science Center for Northern Biosphere, Hokkaido University,
3–8 Chuo-ku, Sapporo 060–0003, Japan
5
Iriomote Station, Tropical Biosphere Research Center, University of the Ryukyus,
870 Uehara, Yaeyama, Taketomi, Okinawa 907–1541, Japan
6
Laboratory of Ecology and Systematics, Faculty of Science, University of the Ryukyus,
1 Senbaru, Nishihara, Okinawa 903–0213, Japan*E-mail: gkokubu@kahaku.go.jp(Received 11 February 2020; accepted 25 March 2020)

Abstract We examined specimens of seed plant taxa collected from the subtropical Ryukyus inthree herbaria at the Facility of Education and at Science, University of the Ryukyus, and at
National Museum of Nature and Science. This examination led to the discovery of 104 new localities for 79 taxa at island level, 19 of which are treated as Japanese-threatened plants.
Key words : conservation, herbarium specimen, island ﬂora, Ryukyus, seed plant, taxonomy,
threatened plants.

Introduction
The Ryukyu Archipelago (hereafter, theRyukyus) comprises approximately 200 islands
spanning 1,300 km between Kyushu of Japan andTaiwan. Biogeographically, the Ryukyus are
divided into ﬁve areas based on ﬂoristic characters of each island (Tagawa and Miyagi, 1991;
Yokota, 1997; Kokubugata et al., 2010). Theseﬁve areas are deﬁned as the northern Ryukyus(the Osumi Islands and the majority of theTokara Islands), the central Ryukyus (the remainder of the Tokara Islands and the Amami andOkinawa Islands), the southern Ryukyus (the© 2020 National Museum of Nature and Science

Miyako and Yaeyama Islands), the Daito Islands
and the Senkaku Islands (Fig. 1). The northern
Ryukyus are temperate, and belong to the SinoJapanese ﬂoristic region; whereas the remaining
four areas are subtropical, and belong to theSoutheast Asiatic ﬂoristic region (Miyawaki,1977).
Within the subtropical Ryukyus, some islands
have been the subject of intensive ﬂoral surveys(e.g., Yokota et al., 1997; Abe et al., 2016; Saito
et al., 2019). On the other hand, comprehensive
ﬂoristic surveys of the subtropical Ryukyus werealso conducted by a number of botanists(Hatusima, 1975; Walker, 1976; Hatusima andAmano, 1994; Shimabuku, 1997), but no surveys
have been conducted since the report producedGoro Kokubugata et al.

76

Fig. 1.

Five biogeographical areas of the Ryukyu Archipelago of Japan.

by Shimabuku (1997). In 2015, we begun investigating and revising the ﬂora of the subtropical
Ryukyus, and completed a regional database, theDatabase of Ryukyu Plants (Ryukyu Plant
Research Group, 2018 onward). Over the courseof the herbarium examinations, we discovered
new localities for seed plants at island level inthe subtropical Ryukyus.
Materials and Methods
Specimens were identiﬁed in the herbaria at
the Faculty of Education (URO) and Science(RYU) at the University of the Ryukyus and at
the National Museum of Nature and Science(TNS). Following identiﬁcation, we checked forexisting records in relevant major ﬂoristic publications (e.g., Hatusima, 1975; Hatusima andAmano, 1994; Shimabuku, 1997), and noted newisland localities discovered for each taxon.
Results and Discussion
We examined 53,917 specimens of 2,168
native seed plant taxa (species, subspecies andvarieties) from 187 families. Among all specimens collected in the subtropical Ryukyus, wefound 104 new localities for 79 taxa in 44 families (Table 1).
The new localities were reported from 27
islands of the subtropical Ryukyus: Kikai-jima (6taxa), Kakeroma-jima (1 taxon), Tokuno-shima

New Localities of Plants from the Ryukyus(6 taxa), Okino-erabu-jima (1 taxon), Yoron-jima(2 taxa) in the Amami Islands; Okinawa-jima (10taxa), Iheya-jima (9 taxa), Izena-jima (5 taxa),
Ie-jima (5 taxa), Tokashiki-jima (5 taxa),
Zamami-jima (1 taxon), Geruma-jima (2 taxa),
Aka-jima (1 taxon), Tonaki-jima (1 taxon),
Kume-jima (6 taxa) in the Okinawa Islands;
Miyako-jima (4 taxa), Ohgami-jima (1 taxon),
Irabu-jima (4 taxa), Shimoji-jima (1 taxon),
Kuruma-jima (1 taxon), Tarama-jima (2 taxa) in
the Miyako Islands; Ishigaki-jima (6 taxa),
Kohama-jima (4 taxa), Iriomote-jima (5 taxa),
Hateruma-jima (3 taxa), Yonaguni-jima (8 taxa)
in the Yaeyama Islands; and Uotsuri-jima (4taxa) in the Senkaku Islands.
Nineteen of the 79 taxa were listed on the Red
List of the Japanese Ministry of Environment(2019; hereafter, RL2019; Table 1). Out of these,
we describe and discuss here conservation, taxonomic and biogeographic features of 12 taxa:
ﬁve critically endangered (CR), two endangered(EN), and ﬁve vulnerable (VU) species.
Deeringia polysperma (Roxb.) Moq. (Amaranthaceae; RL2019: CR; Fig. 2A)
This evergreen vine-shrub has been reported
from the Miyako (Miyako-jima, Ohgami-jimaand Kuruma-jima) and Yaeyama Islands (Ishigaki-jima, Iriomote-jima, Kohama-jima, andHateruma-jima) in the southern Ryukyus; andfrom Taiwan, China, India, and Malaysia (Yokota
et al., 2018a). The populations found on the
Miyako Islands represent the northernmost
known distribution range of this species.
We report a new locality for this species on
Yonaguni-jima of the Yaeyama Islands. Hatusima(1975) previously stated that the Ryukyus plants
are morphologically distinct in terms of both leaf
number and ﬂower size from those found outsideof Japan. It is taxonomically important to investigate these morphological characters on the plantfrom Yonaguni-jima being closest to Taiwan in
the Ryukyus.
Rhus javanica L. var. javanica (Anacardiaceae;
RL2019: CR; Fig. 2B)

77

This small deciduous tree was previously
reported from Ishigaki-jima and Iriomote-jima inthe southern Ryukyus; and from Taiwan, China,
and the Himalayan region (Hatusima, 1975). A
small number of populations are extant on Ishigaki-jima, although the present status of this species on Iriomote-jima is unclear (Tateishi andIha, 2018).
We present a new ﬁnding of a specimen of thisvariety from Miyako-jima in the southern
Ryukyus. This represents a range expansion forthis taxon, as the previous northernmost occurrence was reported ca. 100 km southwest on Ishigaki-jima.
Conyza leucantha (D.Don) Ludlow et Raven(Asteraceae; RL2019: EN; Fig. 2C)This annual or biennial herb has been reported
from Iriomote-jima and Yonaguni-jima in thesouthern Ryukyus; and widely distributes in Taiwan, China, Southeast Asia, and Australia(Yokota and Ikehara, 2018).
We discovered a new occurrence of this species on Ishigaki-jima of the southern Ryukyus,
which is the third record from Japan at islandlevel, and represents the northernmost populationof this species.
Cordia aspera G.Forst. subsp. kanehirae(Hayata) H.Y.Liu (Boraginaceae; RL2019: CR;
Fig. 2D)
This small deciduous tree was previously
reported from Ishigaki-jima, Iriomote-jima in the
Yaeyama Islands, and Uotsuri-jima in the Senkaku Islands (Yonekura, 2017).
We report a new record of this subspecies
from Yonaguni-jima in the Yaeyama Islands,
which is situated near Taiwan. Some taxonomists
treat the Ryukyu plants as C. cumingiana Vidal,
which is distributed in Japan, Taiwan and thePhilippines (e.g., Hatusima, 1975). Therefore,
this record from Yonaguni-jima is important for
determining the taxonomic and phylogeographical relationship between the Ryukyus and Taiwan.

Indo-himo-kazura
Taiwan-fushinoki
Kenashi-tsurumorinka
Ryukyu-mochi
Oh-shiibamochi
No-chidome
Okinawa-chidomegusa
Okinawa-haguma
Niitaka-yomogi
Kazuzaki-kozorina
Ko-yabutabako
Nebari-izu-hahako
Ko-menamomi
Togemino-inuchisha
Kakiba-chishanoki
Kyuri-gusa

Kana-mugura
Hamanindo
Ryukyu-tsuru-umemodoki
Horutokazura
Atsuba-asagao

Ki-karasu-uri
Okinawa-hainezu
Okinawa-juzusuge
Aki-kasasuge
Isoyama-tentsuki

Deeringia polysperma (Roxb.) Moq.
Rhus javanica L. var. javanica

Tylophora tanakae Maxim. var. glabrescens Hatus. ex T.Yamaz.

Ilex liukiuensis Loes.
Ilex warburgii Loes.
Hydrocotyle maritima Honda

Hydrocotyle sibthorpioides Lam. var. tuberifera (Ohwi) T.Yamaz.

Ainsliaea macroclinidioides Hayata var. okinawensis (Hayata) Kitam.
Artemisia morrisonensis Hayata
Blumea lanceolaria (Roxb.) Druce
Carpesium cernuum L.
Conyza leucantha (D.Don) Ludlow et Raven
Sigesbeckia glabrescens (Makino) Makino
Cordia aspera G.Forst. subsp. kanehirae (Hayata) H.Y.Liu
Cordia dichotoma G.Forst.
Trigonotis peduncularis (Trevir.) Benth. ex Hemsl.

Humulus scandens (Lour.) Merr.
Lonicera afﬁnis Hook. et Arn.

Celastrus kusanoi Hayata

Erycibe henryi Prain
Ipomoea imperati (Vahl) Griseb.

Trichosanthes kirilowii Maxim. var. japonica (Miq.) Kitam.
Juniperus taxifolia Hook. et Arn. var. lutchuensis (Koidz.) Satake
Carex ischnostachya Steud. var. fastigiata T.Koyama

Carex nemostachys Steud.
Fimbristylis ferruginea (L.) Vahl var. sieboldii(Miq. ex Franch. et Sav.) Ohwi

Amaranthaceae
Anacardiaceae

Apocynaceae

Aquifoliaceae

Cannabaceae
Caprifoliaceae

Celastraceae

Convolvulaceae

Cucurbitaceae
Cupressaceae
Cyperaceae

Boraginaceae

Asteraceae

Araliaceae

Ogino-tsume
Ryukyu-urokomari

Japanese common name

Hygrophila salicifolia (Vahl) Nees
Lepidagathis inaequalis C.B.Clarke ex Elmer

Species

CR

EN

NT

CR
CR

RL2019status*Collection
dateSouthern Ryukyus, Miyako Islands, Miyako-jima. (Z. Nakasone s.n., TNS58115)
Nov 22, 1937
Central Ryukyus, Okinawa Islands, Kume-jima, Gima-gawa River. (M. Yokota 15319, TNS1183783) Nov 2, 2012
Southern Ryukyus, Miyako Islands, Kuruma-jima. (G. Ikeda 4219, RYU41616)
Sept 26, 1977
Southern Ryukyus, Yaeyama Islands, Yonaguni-jima. (K. Shinjo 5273, URO105165)
July 4, 1967
Southern Ryukyus, Miyako Islands, Miyako-jima, Shimajiri. (S. Isa s.n., RYU12792)
Aug 16, 1969
Southern Ryukyus, Miyako Islands, Miyako-jima, Ohura. (I. Inoue s.n., RYU18082)
July 15, 1970
Senkaku Islands, Uotsuri-jima. (S. Tamaki & Y. Niiro s.n., RYU5128)
Apr 3, 1971
Senkaku Islands, Uotsuri-jima. (Y. Miyagi & S. Hatusima 39965, RYU36234)
Apr 16, 1975
Central Ryukyus, Okinawa Islands, Geruma-jima. (T. Yamazaki 624, TNS325236)
Oct 12, 1972
Senkaku Islands, Uotsuri-jima. (Y. Miyagi & S. Hatusima 39975, RYU36217)
Apr 16, 1975
Southern Ryukyus, Miyako Islands, Shimoji-jima, Kamiji
Dec 4, 1973
(Y. Miyagi, E. Nakada & S. Hatusima s.n., RYU16196)
Central Ryukyus, Amami Islands, Kikai-jima. (K. Yoshinaga 423, RYU35159)
June 21, 1975
Central Ryukyus, Okinawa Islands, Ie-jima, Ie-son Youth Village.
Mar 9, 1995
(H. Ogawa, Y. Tateishi, M. Izu & Y. Nakamoto 820, URO116121)
Central Ryukyus, Okinawa Islands, Tokashiki-jima. (Y. Miyagi & T. Kabashima 4450, RYU21836) May 16, 1974
Southern Ryukyus, Yaeyama Islands, Hateruma-jima, Takana-zaki. (K. Yasuda 6224, TNS1028706) June 25, 2007
Senkaku Islands, Uotsuri-jima. (Y. Niiro & S. Tamaki s.n., RYU2698)
Apr 3, 1971
Southern Ryukyus, Miyako Islands, Irabu-jima. (T. Amano s.n., RYU26592)
July 27, 1950
Southern Ryukyus, Yaeyama Islands, Ishigaki-jima, Mt. Nosoko-dake. (E. Takamine s.n., RYU25654) June, 1947
Central Ryukyus, Amami Islands, Kikai-jima. (K. Yoshinaga 171, RYU46639)
May 5, 1975
Southern Ryukyus, Yaeyama Islands, Yonaguni-jima. (T. Tamaki & Y. Niiro s.n., RYU1550)
Mar 27, 1972
Central Ryukyus, Amami Islands, Tokuno-shima, Omonawa. (H. Migo 26919, TNS373842)
Apr 14, 1966
Central Ryukyus, Okinawa Islands, Izena-jima. (J. Miyagi s.n., RYU10564)
Mar 9, 1971
Southern Ryukyus, Yaeyama Islands, Ishigaki-jima, Yonehara.
Apr 14, 2005
(K. Yasuda, H. Setoguchi & N. Nomura 4006, TNS1029052)
Southern Ryukyus, Yaeyama Islands, Ishigaki-jima, Yonehara.
Apr 14, 2005
(K. Yasuda, H. Setoguchi & N. Nomura 4006, TNS1135143)
Central Ryukyus, Okinawa Islands, Okinawa-jima. (T. Takara s.n., RYU41967)
June 4, 1978
Central Ryukyus, Amami Islands, Tokuno-shima, Takise. (H. Migo s.n., TNS73942)
Apr 12, 1966
Central Ryukyus, Amami Islands, Kakeroma-jima, Akitoku.
Jan 11, 2016
(G. Kokubugata & M. Tabata 18999, TNS1265821)
Central Ryukyus, Amami Islands, Yoron-jima. (Y. Jotani s.n., TNS829744)
Dec 11, 1974
Central Ryukyus, Amami Islands, Yoron-jima. (Y. Jotani s.n., TNS829745)
Dec 11, 1974
Central Ryukyus, Amami Islands, Yoron-jima. (Y. Jotani s.n., TNS829746)
Dec 11, 1974
Central Ryukyus, Okinawa Islands, Kume-jima. (Y. Niiro s.n., RYU18897)
Dec 28, 1957
Southern Ryukyus, Miyako Islands, Irabu-jima. (S. Sakaguchi 18, TNS63609)
Aug, 1922
Southern Ryukyus, Miyako Islands, Irabu-jima. (S. Sakaguchi s.n., TNS63610)
Aug, 1922
Central Ryukyus, Okinawa Islands, Tonaki-jima. (H. Higa s.n., RYU28200)
Oct 8, 1974
Southern Ryukyus, Miyako Islands, Tarama-jima. (Y. Miyagi 7079, RYU37379)
Sept 26, 1975
Central Ryukyus, Okinawa Islands, Okinawa-jima, Naha-shi, Tonokura. (S. Nakamine s.n., S116456) Aug 9, 1954
Southern Ryukyus, Yaeyama Islands, Yonaguni-jima. (K. Shinjo 12782, URO101604)
Mar 9, 1993
Southern Ryukyus, Yaeyama Islands, Iriomote-jima, Ohtomi Forest Road.
Apr 15, 1993
(Y. Kobana 10591, TNS1091824)
Central Ryukyus, Okinawa Islands, Kume-jima. (S. Sakaguchi s.n., TNS220004)
Unknown
Central Ryukyus, Okinawa Islands, Okinawa-jima, Higashi-son, Kesaji Mangrove.
July 27, 1951
(T. Amano 6696, TNS264876)
Southern Ryukyus, Yaeyama Islands, Ishigaki-jima, Nagura-gawa River.
Nov 4, 2004
(K. Yasuda 2980, TNS1028537)

Locality (personal no., herbarium no. of voucher specimen)

New record of seed plants at island level and their voucher specimens and locality information in the subtropical Ryukyus, Japan

Acanthaceae

FamilyTable. 1.
78
Goro Kokubugata et al.

Waniguchi-modama
Amami-arakashi
Nangoku-aoki

Mucuna gigantea (Willd.) DC. subsp. gigantea

Quercus glauca Thunb. var. amamiana (Hatus.) Hatus. ex H.Ohba
Aucuba japonica Thunb. var. ovoidea Koidz.

Lecythidaceae
Linderniaceae

Lauraceae

Lamiaceae

Kogai-zekisho
Inukoju
Mizu-nekono
Ke-shibanikkei
Aogashi
Sagaribana
Tsuru-urikusa

Juncus leschenaultii J.Gay ex Laharpe
Mosla scabra (Thunb.) C.Y.Wu et H.W.Li
Pogostemon stellatus (Lour.) Kuntze
Cinnamomum doederleinii Engl. var. pseudodaphnoides Hatus.
Machilus japonica Siebold et Zucc. ex Blume var. japonica

Barringtonia racemosa (L.) Spreng.
Torenia concolor Lindl.

Helwingia japonica (Thunb.) F.Dietr. subsp.
liukiuensis (Hatus.) H.Hara et S.Kuros.
Hydrocharitaceae Enhalus acoroides (L.f.) Rich. ex Steud.
Hypericaceae
Hypericum laxum (Blume) Koidz.
Juncaceae
Juncus decipiens (Buchenau) Nakai

Helwingiaceae

NT

EN

NT

VU

Tokiwa-yabuhagi

Desmodium leptopus A.Gray ex Benth.

Umi-shobu
Koke-otogiri
Igusa

Hozuki-hagi

Christia obcordata (Poir.) Bakh.f. ex van MeeuwenNT

Shirotsubu

Caesalpinia bonduc (L.) Roxb.

FabaceaeCR

VU

Southern Ryukyus, Yaeyama Islands, Kohama-jima. (Y. Miyagi 6570, RYU37685)
Southern Ryukyus, Yaeyama Islands, Ishigaki-jima, Mt. Omoto-dake. (K. Shinjo 1225, URO108754)
Central Ryukyus, Okinawa Islands, Tokashiki-jima. (Y. Miyagi & S. Oyadomari 1265, RYU9052)
Central Ryukyus, Amami Islands, Kikai-jima. (K. Yoshinaga 1427, RYU40311)
Central Ryukyus, Amami Islands, Tokuno-shima. (Y. Miyagi & S. Hatusima 39551, RYU34181)
Central Ryukyus, Amami Islands, Tokuno-shima. (Y. Jotani & S. Masuda s.n., TNS829262)
Central Ryukyus, Okinawa Islands, Okinawa-jima, Kunigami-son, Oku. (Y. Taira 385, TNS231284)
Central Ryukyus, Okinawa Islands, Ie-jima, Ie Beach. (S. Hatusima 33988, RYU4630)
Southern Ryukyus, Yaeyama Islands, Yonaguni-jima.
(S. Hatusima, Y. Miyagi & E. Nakata 35781, RYU14850)
Central Ryukyus, Okinawa Islands, Tokashiki-jima. (Y. Miyagi & T. Kabashima 4789, RYU22151)
Southern Ryukyus, Yaeyama Islands, Hateruma-jima. (Y. Miyagi 6722, RYU35912)
Central Ryukyus, Amami Islands, Kikai-jima. (K. Yoshinaga 1415, RYU40367)

Nov 4, 2004

Southern Ryukyus, Yaeyama Islands, Ishigaki-jima, Nagura-gawa River.
(K. Yasuda 2980, TNS1028538)
Southern Ryukyus, Yaeyama Islands, Ishigaki-jima, Sakieda. (E. Takamine 148, TNS234709)
Central Ryukyus, Okinawa Islands, Okinawa-jima, Higashi-son, Kesaji. (T. Amano s.n., RYU27724)
Southern Ryukyus, Yaeyama Islands, Iriomote-jima, Mihara. (T. Kitahara 6264, TNS1113778)
Southern Ryukyus, Yaeyama Islands, Kohama-jima. (K. Shinjo & Y. Tateishi 10943, URO102461)
Central Ryukyus, Okinawa Islands, Izena-jima. (E. Nakata s.n., RYU11654)
Central Ryukyus, Okinawa Islands, Kume-jima, Shirase-gawa River. (K. Yasuda 3354, TNS1028546)
Central Ryukyus, Okinawa Islands, Kume-jima, Shirase-gawa River. (K. Yasuda 3354, TNS1028547)
Central Ryukyus, Okinawa Islands, Kume-jima, Shirase-gawa River. (K. Yasuda 3354, TNS1028548)
Southern Ryukyus, Miyako Islands, Miyako-jima, Mt. Ohno-yama. (S. Tawada 979, TNS231834)
Senkaku Islands, Uotsuri-jima. (S. Tawada 75, TNS101578)
Central Ryukyus, Okinawa Islands, Iheya-jima, Dana. (K. Shinjo 729, URO102682)
Central Ryukyus, Okinawa Islands, Izena-jima. (E. Nakada s.n., RYU11652)
Central Ryukyus, Okinawa Islands, Okinawa-jima. (T. Yamazaki & H. Usui 2086, TNS161566)
Southern Ryukyus, Yaeyama Islands, Yonaguni-jima, Higawa.
(G. Kokubugata & M. Yokota 14163, TNS1140521)
Central Ryukyus, Okinawa Islands, Okinawa-jima, Hentona.
(Y. Tateishi, S. Matsumura, T. Yamashiro & E. Tamaki 43517, URO109947)
Central Ryukyus, Okinawa Islands, Okinawa-jima, Hentona.
(Y. Tateishi, S. Matsumura, T. Yamashiro & E. Tamaki 43518, URO109953)
Southern Ryukyus, Miyako Islands, Ohgami-jima.
(G. Kokubugata, M. Yokota, A. Abe 15306, TNS1183781)
Southern Ryukyus, Miyako Islands, Irabu-jima, ground of Sawada Worker Recreation Center.
(Y. Tateishi, H. Ogawa & A. Takada 40298, URO110037)
Southern Ryukyus, Miyako Islands, Irabu-jima. (E. Sugama s.n., URO110036)
Southern Ryukyus, Miyako Islands, Irabu-jima, Sabaoki Park. (M. Amano 1466, URO110034)
Southern Ryukyus, Yaeyama Islands, Yonaguni-jima. (S. Hatusima, H. Kanai, K. Shimabuku,
Y. Miyagi, E. Nakata, & M. Furuse 732234 , TNS297054)
Central Ryukyus, Amami Islands, Tokuno-shima, seaside of Ohtsu-gawa River.
(G. Kokubugata, M. Yokota & H. Yamashita 12477, TNS01103877)
Central Ryukyus, Amami Islands, Kikai-jima. (K. Yoshinaga 1327, RYU40347)
Central Ryukyus, Okinawa Islands, Iheya-jima. (K. Shinjo 2030, URO114592)
Central Ryukyus, Okinawa Islands, Tokashiki-jima. (Y. Miyagi & T. Kabashima 4452, RYU21745)
Central Ryukyus, Okinawa Islands, Kume-jima, Oh-dake. (F. Maekawa s.n., TNS882512)

May 16, 1974
July 9, 1975
Sept 15, 1977

July 7, 1975
Mar 2, 1957
May 6, 1973
Sept 15, 1977
Feb 12, 1975
July 12, 1973
Sept 26, 1938
May 21, 1972
Sept 29, 1973

Aug 9, 1977
Jan 8, 1958
May 16, 1974
Feb 15, 1974

Feb 7, 2010

Apr 12, 1996
June 12, 2012
Sept 30, 1973

Sept 18, 1994

Oct 22, 2012

June 28, 1996

June 28, 1996

July 24, 1938
July 22, 1951
July 6, 2007
Mar 26, 1998
Aug 23, 1973
Jan 17, 2005
Jan 17, 2005
Jan 17, 2005
Aug 22, 1942
Apr 16, 1952
Dec 29, 1956
Aug 23, 1973
Dec 20, 1963
Oct 19, 2001

Collection
date

Locality (personal no., herbarium no. of voucher specimen)

Continued.
RL2019status*Ryukyu-hanaikada

Suisya-hoshikusa

Fagaceae
Garryaceae

Nebikigusa

Machaerina rubiginosa (Sol. ex G.Forst.) T.Koyama

Eriocaulon truncatum Buch.-Ham. ex Mart.

Tsukushi-tentsuki
KurogayaOh-hinji-gayatsuri
Hinji-gayatsuri

Japanese common nameFimbristylis tashiroana Ohwi
Gahnia tristis Nees
Lipocarpha chinensis (Osbeck) Kern
Lipocarpha microcephala (R.Br.) Kunth

Species

Eriocaulaceae

FamilyTable. 1.

New Localities of Plants from the Ryukyus
79Hime-itabi

Okinawa-sokei
Ke-mizukimbai
Niraba-ran

Ficus thunbergii Maxim.

Jasminum superﬂuum Koidz.
Ludwigia adscendens (L.) H.Hara
Microtis parviﬂora R.Br.

Zeuxine strateumatica (L.) Schltr.
Kinu-ran
Corydalis heterocarpa Siebold et Zucc. var. brachystyla (Koidz.) Ohwi Munin-kikeman

Oleaceae
Onagraceae
Orchidaceae

Papaveraceae

SasagayaNumeri-gusa
Mamakono-shirinugui
Bakuchinoki
Ryukyu-ichigo

Microstegium japonicum (Miq.) Koidz.

Persicaria senticosa (Meisn.) H.Gross

Prunus zippeliana Miq.
Rubus grayanus Maxim.

Polygonaceae

Rosaceae

Hime-chigozasa
Hitotaba-mehishiba
Taiwan-ashikaki
Azegaya

Cyrtococcum patens (L.) A.Camus
Digitaria pruriens (Fisch. ex Trin.) Büse
Leersia hexandra Sw.
Leptochloa chinensis (L.) Nees

Poaceae

Sacciolepis indica (L.) Chase var. oryzetorum (Makino) Ohwi

Suzumeno-hakobe
Kirun-kankonoki

Microcarpaea minima (K.D.Koenig ex Retz.) Merr.
Glochidion lanceolatum Hayata

Phrymaceae
Phyllanthaceae

Amami-hisakaki

Hime-shiroasaza
Ohba-ako

Nymphoides coreana (H.Lév.) H.Hara
Ficus caulocarpa (Miq.) Miq.

Menyanthaceae
Moraceae

Pentaphylacaceae Eurya osimensis Masam.

Horai-tsuzurafuji

Japanese common name

Pericampylus formosanus Diels

Species

Menispermaceae

FamilyTable. 1.

NT
NT

VU
VU

VU

CR

Locality (personal no., herbarium no. of voucher specimen)

Collection
dateSouthern Ryukyus, Yaeyama Islands, Ishigaki-jima, Nagura-gawa River.
Feb 4, 2007
(K. Yasuda, M. Yokota, S. Higa, H. Tomiyama, S. Matsushima & T. Kitahara 5260, TNS1114499)
Southern Ryukyus, Miyako Islands, Irabu-jima. (T. Amano s.n., RYU25348)
July 27, 1950
Central Ryukyus, Okinawa Islands, Okinawa-jima, Nakijin-son, Wakugawa.
Apr 29, 1939
(T. Kanasiro s.n., RYU25419)
Central Ryukyus, Okinawa Islands, Tokashiki-jima. (K. Shimabuku 4188, RYU41284)
July 8, 1978
Central Ryukyus, Okinawa Islands, Iheya-jima. (Y. Niiro s.n., RYU19855)
Dec 28, 1958
Southern Ryukyus, Yaeyama Islands, Yonaguni-jima.
Oct 3, 1973
(S. Hatusima, H. Kanai, K. Shimabuku, Y. Miyagi & E. Nakata 722362, TNS318258)
Southern Ryukyus, Yaeyama Islands, Yonaguni-jima. (Y. Jotani 38537, TNS849315)
May 5, 1981
Central Ryukyus, Okinawa Islands, Iheya-jima. (S. Kayô s.n., RYU10349)
Aug 29, 1970
Southern Ryukyus, Yaeyama Islands, Kohama-jima. (Y. Miyagi 6535, RYU37649)
July 7, 1975
Central Ryukyus, Okinawa Islands, Iheya-jima, Mt. Kuba-yama.
May 4, 1995
(K. Shinjo & Y. Tateishi 790, URO104569)
Central Ryukyus, Okinawa Islands, Izena-jima. (J. Miyagi s.n., RYU11178)
Mar 9, 1971
Central Ryukyus, Amami Islands, Yoron-jima. (J. Haginiwa 016754, TNS966754)
Dec 24, 1971
Central Ryukyus, Amami Islands, Yoron-jima. (J. Haginiwa 016755, TNS966755)
Dec 24, 1971
Central Ryukyus, Amami Islands, Kikai-jima, Akaren. (H. Murakami 437, TNS689342)
Apr 19, 1998
Southern Ryukyus, Yaeyama Islands, Iriomote-jima, Mt. Komi-dake.
Dec 21, 2004
(G. Kokubugata, M. Yokota & K. Yasuda 5458, TNS9519088)
Southern Ryukyus, Yaeyama Islands, Iriomote-jima, Aira-gawa River. (K. Yasuda 5376, TNS1119995) Mar 13, 2007
Southern Ryukyus, Yaeyama Islands, Iriomote-jima. (S. Kurata & T. Nakaike 330, TNS369367)
June 1, 1973
Dec 21, 2004
Southern Ryukyus, Yaeyama Islands, Iriomote-jima, Mt. Komi-dake.
(G. Kokubugata, M. Yokota & K. Yasuda 5403, TNS9519036)
Southern Ryukyus, Yaeyama Islands, Iriomote-jima, Mt. Komi-dake.
Dec 21, 2004
(G. Kokubugata, M. Yokota & K. Yasuda 5404, TNS9519037)
Southern Ryukyus, Yaeyama Islands, Iriomote-jima, Udara-gawa, River.
Mar 24, 2007
(K. Yasuda, M. Yokota, G. Kokubugata, S. Higa, H. Tomiyama & T. Kitahara 5395, TNS1119720)
Southern Ryukyus, Yaeyama Islands, Iriomote-jima, Aira-gawa River. (K. Yasuda 5376, TNS1119994) Mar 13, 2007
Southern Ryukyus, Yaeyama Islands, Iriomote-jima, Urauchi-gawa River.
Oct 24, 2008
(G. Kokubugata 11151, TNS9543099)
Central Ryukyus, Okinawa Islands, Iheya-jima. (S. Hatusima & al. 35089, RYU11694)
July 23, 1973
Central Ryukyus, Okinawa Islands, Iheya-jima. (S. Hatusima & al. 35085, RYU11698)
July 24, 1973
Central Ryukyus, Okinawa Islands, Iheya-jima. (S. Hatusima & al. 35117, RYU11726)
July 24, 1973
Central Ryukyus, Okinawa Islands, Aka-jima. (Y. Miyagi 7931, RYU42957)
Aug 12, 1977
Central Ryukyus, Okinawa Islands, Aka-jima. (Y. Miyagi 7751, RYU44160)
Aug 12, 1977
Southern Ryukyus, Yaeyama Islands, Hateruma-jima. (Y. Miyagi 6711, RYU38103)
July 9, 1975
Central Ryukyus, Okinawa Islands, Zamami-jima. (Y. Niiro & Y. Miyagi 3071, RYU3050)
Sept 14, 1973
Central Ryukyus, Okinawa Islands, Ie-jima. (S. Kayô s.n., RYU20672)
Apr, 1971
Central Ryukyus, Okinawa Islands, Okinawa-jima, Naha-shi, Tsuboya. (Y. Taira 278, TNS233978) June 19, 1938
Southern Ryukyus, Yaeyama Islands, Iriomote-jima, Hoshidate. (K. Yasuda 2720, TNS1028241)
June 10, 2004
Central Ryukyus, Okinawa Islands, Okinawa-jima, Mt. Yonaha-dake. (S. Tamaki s.n., RYU2887)
Nov 8, 1970
Southern Ryukyus, Yaeyama Islands, Iriomote-jima, Shirahama. (M. Furuse 3012, RYU11158)
Apr 22, 1973
Central Ryukyus, Okinawa Islands, Ie-jima. (S. Kayô s.n., RYU19560)
May 22, 1970
Central Ryukyus, Okinawa Islands, Iheya-jima. (S. Kayô s.n., RYU19562)
Aug, 1970
Central Ryukyus, Amami Islands, Okino-erabu-jima. (S. Hatusima & Y. Miyagi 39004, RYU31399) Dec 10, 1974
Central Ryukyus, Okinawa Islands, Kume-jima. (C. Shiroma s.n., TNS1065846)
July, 1919
Southern Ryukyus, Yaeyama Islands, Ishigaki-jima, Kabira. (T. Amano 7298, TNS116325)
Apr 19, 1954
Central Ryukyus, Okinawa Islands, Iheya-jima. (S. Hatusima & al. 35107, RYU11730)
July 24, 1973
Central Ryukyus, Okinawa Islands, Geruma-jima. (Y. Niiro s.n., RYU2832)
Aug 15, 1960

Continued.
RL2019status*80
Goro Kokubugata et al.

Sept 26, 1975
July 11, 1973
July 11, 1973
Mar 26, 1998
May 4, 1974

Aug 29, 1970
Aug 9, 1894
Sept 29, 1973

Central Ryukyus, Okinawa Islands, Iheya-jima, Mt. Kayo-san. (M. Kugai s.n., RYU6327)
Southern Ryukyus, Miyako Islands, Miyako-jima. (T. Ito 168, TNS382406)
Southern Ryukyus, Yaeyama Islands, Yonaguni-jima.
(S. Hatusima, Y. Miyagi & E. Nakata 35809, RYU14685)
Southern Ryukyus, Yaeyama Islands, Yonaguni-jima.
(S. Hatusima, Y. Miyagi & E. Nakata 35517, RYU15847)
Southern Ryukyus, Miyako Islands, Tarama-jima. (Y. Miyagi s.n., RYU37424)
Central Ryukyus, Amami Islands, Tokuno-shima. (Y. Jotani & S. Masuda s.n., TNS825502)
Central Ryukyus, Amami Islands, Tokuno-shima. (Y. Jotani & S. Masuda s.n., TNS825515)
Southern Ryukyus, Yaeyama Islands, Kohama-jima. (K. Shinjo & Y. Tateishi 10954, URO112873)
Central Ryukyus, Okinawa Islands, Ie-jima. (S. Hatusima & Y. Miyagi 37400, RYU21898)
Hana-shinbogi
Iwa-zansho

Boroboronoki
Aragata-sankirai

Glycosmis citrifolia (Willd.) Lindl.
Zanthoxylum beecheyanum K.Koch

Schoepﬁa jasminodora Siebold et Zucc.
Smilax bracteata C.Presl var. verruculosa (Merr.) T.Koyama
Schoepﬁaceae
Smilacaceae

Aridoshi
BochojiTachibana
Rubiaceae

Rutaceae

Damnacanthus indicus Gaertn.f. var. indicus
Psychotria rubra (Lour.) Poir.
Citrus tachibana (Makino) Tanaka

NT

Sept 29, 1973

Collection
date
Locality (personal no., herbarium no. of voucher specimen)
RL2019status*Japanese common nameSpecies
FamilyTable. 1.

Continued.

New Localities of Plants from the Ryukyus

81

Fimbristylis dichotoma (L.) Vahl subsp. podocarpa (Nees et Meyen) T.Koyama (Cyperaceae;
RL2019: VU; Fig. 3A)
This perennial sedge has been reported from
Okinawa-jima in the central Ryukyus and Ishigaki-jima in the southern Ryukyus; from
Kyushu of Japan; and is widely distributed inIndia, Malaysia, and the Paciﬁc Islands (Yokota
and Nakata, 2018). Three and one populations
are respectively known from Okinawa-jima andIshigaki-jima at present (Yokota and Nakata,2018).
We report a new locality for this species on
Iriomote-jima in the southern Ryukyus. Sometaxonomists treat the Ryukyu plants as F. tashiroana Ohwi being endemic to Japan (Ohwi, 1931).
Therefore, further study is required to investigate
the endemism of the plants from Japan including
Iriomote-jima.
Eriocaulon truncatum Buch.-Ham. ex Mart.
(Eriocaulaceae; RL2019: CR; Fig. 3B)
This helophyte grass was previously reported
from Tokuno-shima, Okinawa-jima, Kume-jimain the central Ryukyus, Ishigaki-jima, Iriomotejima and Yonaguni-jima in the southern Ryukyus(Tateishi et al., 2018a); and from Taiwan, China,
Indochina, the Philippines and Thailand(Miyamoto, 2015). Although several populations
occur in the northern and central parts of Okinawa-jima, the majority of populations havebeen destroyed by anthropogenic development(Tateishi et al., 2018a). A few populations are
known from Ishigaki-jima and Iriomote-jima, but
the present status of populations occurring onother islands is unclear (Tateishi et al., 2018a).
We recorded a ﬁrst occurrence of E. truncatumfrom Dana, Iheya-jima in the central Ryukyus.
The locality includes a wetland habitat, andmany helophyte species have been reported fromthis area (Niiro and Shinzato, 1978). However,these wetlands are threatened by ongoing development and the spread of naturalized plant species. Some taxonomists treat the Ryukyu plants
as Eriocaulon nigrum Lecomte var. suishaense(Hayata) Hatusima et T.Koyama distributed in82

Goro Kokubugata et al.

the Ryukyus, Taiwan, China and Indochina (e.g.,
Hatusima, 1975; Walker, 1976; Tateishi et al.,2018a). Therefore, further studies are required tounderstand the taxonomy of the plants from the
Ryukyus and in particular from Iheya-jima.
Enhalus acoroides (L.f.) Rich. ex Steud.
(Hydrocharitaceae; RL2019: VU; Fig. 3C)
This submerged growing seagrass has beenreported from Ishigaki-jima, Iriomote-jima andYonaguni-jima in the Yaeyama Islands; and is
widely distributed from Indochina to Australia
and Africa (Yokota and Yasuda, 2018). Some
populations of this species are known from Ishigaki-jima and Iriomote-jima, while the present
status of population in Yonaguni-jima is not clear(Yokota and Yasuda, 2018).
We report a new locality from Kohama-jima in
the Yaeyama Islands. Kohama-jima is situatedbetween Ishigaki-jima and Iriomote-jima, andtreated as one of the Sekisei Lagoon Islets withother eight islets (Chinen, 1993). Given this ﬁnding, we suspect that this species may occur onother islets in the Sekisei Lagoon Islets too.
Torenia concolor Lindl. (Linderniaceae;
RL2019: EN; Fig. 3D)This trailing perennial herb was previously
reported from Amami-ohshima, Uke-jima, Okinawa-jima in the central Ryukyus, and Miyakojima in the southern Ryukyus; and from Taiwan,
China, Southeast Asia, India and Sri Lanka(Ohashi, 2017). We conﬁrmed that several populations persist on Amami-ohshima by our recent
ﬁeld survey conducted in 2019, but we could not
conﬁrm the population on Kikai-jima in our ﬁeld
survey conducted in 2017 (details not shown). It
is likely that the populations on Okinawa-jimaand Miyako-jima in the Ryukyus have become
extinct (Tateishi et al., 2018b).
We report a new record of this species from
Kikai-jima, which is the third record from theAmami Islands in the central Ryukyus. However,this species may have come from a populationthat is now extirpated, as we did not ﬁnd anyother plant of this species during our detailed

surveys on Kikai-jima conducted in 2009 (details
not shown). Some taxonomists treat the Ryukyus
plants as T. concolor var. formosana Yamazaki
distributing in only the Ryukyus and Taiwan(Tateishi et al., 2018b). Therefore, comparative
surveys including plants from Southeast Asia,
India and Sri Lanka are necessary to understandits taxonomic status.
Pericampylus formosanus Diels (Menispermaceae; RL2019:CR; Fig. 4A)
This perennial vine was previously reported
from only Miyako-jima in the southern Ryukyus;
and from Taiwan and southern part of China(Hatusima, 1975), but the present status of thisspecies on the Miyako population is unclear(Shinjo and Kawakami, 2018).
We report a new record of this species from
Ishigaki-jima, which is the second record fromJapan at island level.
Nymphoides coreana (H.Lév.) H.Hara (Menyanthaceae; RL2019: VU; Fig. 4B)
This ﬂoating aquatic has been reported from
Miyako-jima, Ishigaki-jima, Iriomote-jima,
Kayama-jima, and Yonaguni-jima in the southern
Ryukyus; from Honshu, Shikoku, and Kyushu ofJapan, Korea and China (Tateishi et al., 2018c).
The present status of populations in Miyako-jima
are not clear, while some populations of this species are known from the reminder islands (Tateishi et al., 2018c).
We report a new locality for this species on
Irabu-jima, which is the second recorded occurrence from the Miyako Islands.
Jasminum superﬂuum Koidz. (Oleaceae;
RL2019: VU; Fig. 4C)
This woody vine has been reported from
Kikai-jima, Yoron-jima, Okinawa-jima in thecentral Ryukyus, Miyako-jima, Irabu-jima, andIshigaki-jima in the southern Ryukyus; and from
Taiwan (Hatusima, 1971). This species was also
found from Sesoko-jima of the central Ryukyus(Shimabuku, 1973).
We report a locality from Iheya-jima being an

New Localities of Plants from the Ryukyus

Fig. 2. Voucher specimen for new record at island level in the subtropical Ryukyus. A. Deeringia polysperma(Amaranthaceae; RYU). B. Rhus javanica var. javanica (Anacardiaceae; RYU). C. Conyza leucantha (Asteraceae; RYU). D. Cordia aspera subsp. kanehirae (Boraginaceae; RYU). Scale bars = 3 cm.

83

Goro Kokubugata et al.

84

Fig. 3. Voucher specimen for new record at island level in the subtropical Ryukyus. A. Fimbristylis tashiroana(Cyperaceae; TNS). B. Eriocaulon truncatum (Eriocaulaceae; URO). C. Enhalus acoroides (Hydrocharitaceae; RYU). D. Torenia concolor (Linderniaceae; RYU). Scale bars = 3 cm.

New Localities of Plants from the Ryukyus

Fig. 4. Voucher specimen for new record at island level in the subtropical Ryukyus. A. Pericampylus formosanus(Menispermaceae; TNS). B. Nymphoides coreana （Menyanthaceae; RYU). C. Jasminum superﬂuum (Oleaceae; RYU). D. Ludwigia adscendens (Onagraceae). Scale bars = 3 cm.

85

Goro Kokubugata et al.

86

islet adjacent to Okinawa-jima, which is the third
occurrence from the Okinawa Islands. Taxonomically, Hatusima (1975) treated the Ryukyus
plants as J. sinensis Hemsl. distributed in the
Ryukyus and southern part of China. Thus, further taxonomic studies based on the plants fromthe Ryukyu, Taiwan and China are required.
Ludwigia adscendens (L.) H.Hara (Onagraceae;
RL2019: VU; Fig. 4D)This hydrophyte herbaceous species has beenreported from Okinawa-jima in the central
Ryukyus, the Daito Islands, the Miyako Islands,
and Ishigaki-jima in the southern Ryukyus; andis widely distributed in Taiwan and tropical areasof Asia (Hatusima, 1975). Populations on the
Miyako Islands have declined because of anthropogenic activities, and only one population is
known from Ishigaki-jima in the Yaeyama
Islands (Yokota et al., 2018b).
We report a new locality of this species on
Kohama-Jima, which is the second record for the
Yaeyama Islands. Given this ﬁnding on Kohamajima, we suspect that this species may also occur
on other islets in the Sekisei Lagoon Islets.
Acknowledgments
This study was supported by a project of “Biological Properties of Biodiversity Hotspots inJapan” conducted by the National Museum of
Nature and Science, Tokyo.
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