Bull. Natn. Sci . Mus., Tokyo, Ser. B, 28(3), pp. 99- 106, September 22, 2002

Taxonomic Studies of Cirsium (Asteraceae) in Japan VIII.
Cirsium shidokimontanum, a New Species from Middle Honshu
Yuichi Kadota
Department of Botany, National Science Museum,4- 1- 1 Amakubo, Tsukuba, Japan 305- 0005
E-mail: kadota@kahaku.go.jp

Abstract Cirsium shidokimontanum Kadota is here described from middle Honshu. Cirsium shidokimontanum is distinguished from C. abukumense and C. nipponicum var. incomptum by having
fle shy leaf blades, cylindrical involucres and 9- 11-seriate involucra! phyllaries. Cirsium shidokimontanum is endemic to Japan and is distributed in Fukushima, Tochigi and Nagana Prefectures.
Key words: Cirsium , Cirsium abukumense, Cirsium albrechtii, Cirs ium heiianum , Cirsium nipponicum var. incomptum, Cirsium shidokimontanum, Honshu, Japan, new species.

In the course of systematic studies on thegenus Cirsium of Japan I have conducted extensive field works throughout Japan and have reported some results of the studies (Kadota, 1989,1990, 1991, 1993, 1995a, 1995b, 1996, 1997a,1997b, 1998~ 1998b, 1999,2000).
In 1995 I found unknown thistles near Ogawa,
Kita-lbaraki , Ibaraki Pref. , the Kanto District,middle Honshu. I had made field researches repeatedly in the Abukuma Highlands because thelocality "Ogawa" is located around the southernend of the Highlands. As a result it is clarified
that this thistle belongs to a distinct species andis distributed in throughout the Abukuma Highlands. Further field explorations have revealed
that this species is also distributed in Tochigi andNagana Prefectures. Here I will describe thisnew species of Cirsium as C. shidokimontanum
because the first discovery site "Ogawa" is located near the River Shidokigawa, a tributary of theRiver Samekawa which runs to the PacificOcean.
Taxonomic treatment
Sect. Onotrophe (Cass.) DC. , Prodr. 6: 644( 1837).
Subsect. Tubelosae Kitam . in Acta Phytotax.

Geobot. 3: 5 (1934), p. p.
Cirsium shidokimontanum Kadota, sp. nov.
[Figs. 1- 3]
Cirsium heiianum auct. non Koidz.: Okuhara,
Shinshu-no-Yaso 91, bottom photo ( 1990) Kadota in T.Shimizu & al., Fl. Nagana Pref.
1137 (1997).
Differt ab Cirsio abukumenso et C. nipponico
var. incompto laminis foliaorum carnosis, involucris cylindricis et phyllriis 9- 11-serialibus.
TYPUS. JAPAN: Honshu; Fukushima Pref. ,Higashi-shirakawa-gun, Furudono-machi, Mt.
Mikabuyama, alt. 585 m, along a stream in tall
herbal stand, 26 September 1999, Y. Kadota
997001 (TNS-holotypus; Fig. 1). lbaraki Pref.,Kita-lbaraki-shi , Ogawa, alt. 700 m, along a tributary of the River Shidokigawa, Y. Kadota
997008 (TNS- paratypus).
A robust perennial herb, 1.2- 2.4 m tall. Rootstock well developed, stout, horizontal , up to I 0
cm in diameter, with cord-like roots. Stem erect,
well branched from the middle part of the stem,
covered with brownish multicellular hairs andarachnoid in the upper half. Basal leaves withering at anthesis. Middle cauline leaves green
above, fleshy, broadly ovate to broadly elliptic,
30--40 cm long, 15- 26 cm wide, medi ally todeeply pinnatilobate with 5- 7-juga or sometimes

100Yuichi Kadota

Fig. I. Holotype of Cirsium shidokimontanum Kadota (Honshu , Fukushima Pref. , Higashi-shirakawa-gun,Furudono-machi, Mt. Mikabuyama, alt. 585 m, 26 September 1999, Y. Kadota 99700 I, TNS). Right cornerinset shows a close-up of capitulum of the same individual.

Cirsium shidokimontanum, a New Species from Middle Honshu

101

Fig. 2. Habit of Cirsium shidokimontanum Kadota (Honshu, Fukushima Pref., Higashi-shirakawa-gun,Furudono-machi , Mt. Mikabuyama, the type locality, a it. 585 m, on 26 September 1999). Ri ght cornerinset shows a nodding capitulum with ascending involucra! phyllaries of the same individual.

102

Yuichi Kadota

Fig. 3. Habit of Cirsiurn shidokirnontanurn Kadota. (Honshu, Tochigi Pref. , Nasu-gun, Nasu-machi , Otani , alt.
430 m, on 5 October 1999). Right corner inset shows an oblique capitulum with patent or slightly reflexed invo lucra! phyllaries of the same individual.

Cirsium shidokimontanum , a New Species from Middle Honshu

simple and serrulate, provided with weak spines
2- 3 mm long along margin, glabrous on theadaxial side, pubescent with brownish multicellular hairs along veins on the abaxial side, shortlypetiolate. Flowers in September to October. Capitula 5- 7 in a loose terminal raceme, nodding(Fig. 2) or sometimes ascending to erect (in thecase of subsessile or shortly pedunculate capitula; Fig. 3) ; peduncles 0.5-4 cm long or subsessile, covered with brownish multicellular hairs
and/or arachnoid; subtending leaf solitary or absent, narrowly lanceolate, ea. I cm long, provided
with weak spines I mm long. lnvolucres cylindrical, more or less purplish, not glutinous or sometimes slightly glutinous, 16- 20 mm long, 6- 10mm (in vivo) and 16- 20 mm (in sicco) in diameter, sparingly arachnoid. Phyllaries 9- 11-seriate,
herbaceous, terminated with weak spines ea. I
mm long; glandular bodies absent or sometimes
with elliptic glandular bodies on the abaxial side103of middle phyllaries; inner ones narrowly ovate,ea. 1.5 cm long, erect; outer ones narrowly ovatewith acuminate tips, 5-8 mm long, reflexed to ascending, highly variable in extending direction ofthe middle and the outer phyllaries. Corollae paleviolet, 15- 17 mm long; lobes ea. 3 mm long;
throats ea. 6 mm long ; tubes 7- 8 mm long, longer
than the throats. Achenes grayish brown, 3-4mm long, smooth; pappi sordid, 12- 17 mm long .
Chromosome number: 2n=4x=68 (Fig. 4).
Japanese name: Shidoki-yama-azami (nov.) .
Distribution: Honshu (Fukushima, lbaraki ,Tochigi and Nagano Prefs.; Fig. 5). Endemic toJapan. Along streams and lakes in herbal stands
and on the margin of summer-green or mixedforests : 400-800 m.
Specimens examined:
JAPAN : Honshu; Fukushima Pref. , Somagun, Katsurao-mura, Noboritae Pass, alt. 580 m,
27 September 1999, Y. Kadota 997022-997023••0...--"

Fig. 4. Somatic chromosomes of Cirsium shidokimontanum Kadota (Voucher specimen: Honshu , Nagana Pref. ,Chino-shi , the Lake Tateshina, a it. 1235 m, Y. Kadota 201227, TNS 71003 7).

104Yuichi Kadota

2SO

500

0~Fig. 5.

Distribution ofCirsium shidokimontanum Kadota.

(TNS). Tamura-gun, Ogoe-machi, Mt. Otakineyama, Onigoro, alt. 790 m, 5 October 1998, Y.
Kadota 986043- 986056 (TNS). Higashi-shirakawa-gun, Furudono-machi, Mt. Mikabuyama,alt. 620 m, 6 October 1998, Y. Kadota
986076- 986084 (TNS); Mt. Mikabuyama, alt.
585 m, along a stream in tall herb stand, 26 September 1999, Y. Kadota 997002- 997006 (TNS).
Koriyama-shi, Mt. Ippaiyama, Nanatsuwan, alt.
560 m, 27 September 1999, Y. Kadota 997015997018 (TNS). Iwase-gun, Ten' ei-mura, Hatori,
alt. 710m, 7 October 1999, Y. Kadota 997107997111 (TNS).
lbaraki Pref. , Kita-Ibaraki-shi , Ogawa, alt.
700 m, 4 October 1998, Y. Kadota 986006986015,986017- 986018 (TNS); Ogawa, alt. 700m, along a tributary of the River Shidokigawa, Y.
Kadota 997009-997013 (TNS).
Tochigi Pref. , Kuroiso-shi, Miyama, alt. 570
m, along a tributary of the River Nakagawa, 5October 1999, Y. Kadota 997023- 997035 (TNS).
Nasu-shi, Kofukabori, alt. 480 m, 4 October
1999, Y. Kadota 997102- 997102 (TNS). Nasugun, Nasu-machi, Otani, alt. 430 m, 5 October
1999, Y. Kadota 997112- 997123 (TNS).
Nagano Pref., Chino-shi, near the LakeTateshina, alt. 1235m, 10 October 2001, Y.
Kadota 201227 (TNS 710037; voucher specimenof the chromosome number 2n=4x=68).
Cirsium shidokimontanum is distinguishedfrom C. abukumense Kadota and C. nipponicum(Maxim.) Matsum. var. incomptum Kitam . ex

Cirsium shidokimontanum, a New Species from Middle Honshu

Ohwi by having fleshy cauline leaves, cylindricalinvolucres and 9- ll-seriate involucra! phyllaries.
The three taxa are distributed together in middle
Honshu (chiefly on the Pacific Ocean side) . Cirsium shidokimontanum prefers rather wet places(along streams and lakes) whike C. abukumenseand C. nipponicum var. incomptum are found in
grassland and on the margin of forests on xeric
soils. In this way habitat segregation among thethree taxa is observed especially on the Pacific
Ocean side of middle Honshu in the lowland
tetraploid species group.
Cirsium heiianum Koidz. from northen Honshu (a distinct entity fromHokkaido
populations=C. a/brechtii (Maxim.) Kudo exTatew.; Kadota, unpublished) and C. congestissimum Kitam. from western honshu are superficially similar to C. shidokimontaum in having wellbranched and erect stem, numerous capitula withcylindrical involucres and 9-seriate involucra!
phyllaries. However, C. shidokimontanum is discriminated from C. heiianum and C. congestissimum by the plody level (2n=4x=68 vs. 2n=2x=34) and the extending direction of capitula (nodding or occasionally oblique to suberect vs. erect
to oblique).

Acknowledgements
I am grateful to Professor Dr. Tsunehiko
Nishikawa, Hokkaido University of Education,
Asahikawa, for the count and taking pictures ofchromosomes in Cirsium shidokimontanum; toDr. Yoichi Yuzawa and Mmes. Eiko Fukazawa,
Nanami Kon'no and Masako Tanihira, Iwaki
City, Fukushima Prefecture, for the guidance andhelp of field researches in the Abukuma Mountains of Fukushima Prefecture; to Mr. Kenji Hasunuma for the help of field researches in theAizu Region of Fukushima Prefecture; to Mr.
Kenju Imai for the guidance of the localities ofCirsium shidokimontanum in the Nagano Prefecture.

105

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