Bull. Natl. Mus. Nat. Sci., Ser. B, 35(1), pp. 41–49, March 22, 2009

Taxonomic Studies of Cirsium (Asteraceae) in Japan XIX.
Two New Species from Honshu, Central Japan
Yuichi Kadota
Department of Botany, National Museum of Nature and Science,
Amakubo 4–1–1, Tsukuba, 305–0005 Japan
E-mail: kadota@kahaku.go.jp

Abstract Cirsium myokoense Kadota is described from Niigata Pref., Honshu, and is distinguished from C. tenuipedunculatum Kadota by having thicker, cylindrical involucres, patent andlonger involucral phyllaries, longer and thicker peduncles, membranous, ovate to broadly ovate,
medially pinnatilobate cauline leaves and the absence of glandular bodies on inner and middle involucral phyllaries. Cirsium nagisoense Kadota is described from Nagano Pref. and is distinguished from C. furusei Kitam. by having cauline leaf blades glaucous (not woolly) below, adpressed, non spinulose involucral phyllaries and oblong to oblanceolate glandular bodies on bodies
on all the involucral phyllaries. Both C. myokoense and C. nagisoense are endemic to Honshu,
Japan, and belong to sect. Onotrophe (Cass.) DC. subsect. Reflexae Kadota (the Cirsium kagamontanum group).
Key words : Cirsium kisoense, Cirsium myokoense, Cirsium nagisoense, Cirsium spinuliferum,
Japan, new combinations, new species.

Introduction
This is part of a revisional work on JapaneseCirsium (Asteraceae) (Kadota, 1989–2008;
Kadota and Nagase, 1988).
Subsect. Reflexae Kadota of sect. Onotrophe(Cass.) DC. ( the Cirsium kagamontanumgroup) is characterized by the absence of radical
leaves, nodding heads, narrowly cylindrical tocylindrical involucres and the chromosome number of 2n2x34 and is considered to be a plantgroup that is extraordinarily differentiated in
Honshu and Shikoku Islands, the Japanese Archipelagoes (Kadota, 2007b). Within this plantgroup there still remain several undescribed taxa
especially in the central part of Honshu. Here I
describe two new species from Honshu in thesubsect. Reflexae.

Taxonomic treatment
Genus Cirsium Mill., Gard. Dict. Abringd. ed. 4,
1 (1754), emend. Scop., Fl. Carn. 355 (1760).

Sect. Onotrophe (Cass.) DC., Prodr. 6: 644(1837).
Genus Onotrophe Cass. in Dict. Sci. Nat. 36: 145(1825).
Ser. Onotrophe (Cass.) Maxim. in Bull. Acad.
Sci. St.-Pétersb. 19: 502 (1874).
Subsect. Reflexae (Kitam.) Kadota, Fl. Jap. IIIa:
148 (1995).
Ser. Reflexe Kitam. in Acta Phytotax. Geobot. 3:
5 (1934), p. p.
Ser. Imbricatae Kitam. in Acta Phytotax. Geobot.
3: 5 (1934), p. p.
1.

Cirsium myokoense Kadota, sp. nov.
[Figs. 1 and 2]
Differt ab Cirsio tenuipedunculato, caule beneramoso ramis divaricatis, phyllariis involucrorum(8–)9–10-seriatis, flosculis longioribus, pedunculis crassioribus, acheniis costatis; ab C. horiiano, caule bene ramoso ramis divaricatis, pedunculis crassioribus, foliis mediis caulinis pinnatilobatis, vittis vestigialibus non nisi superphyllariis involucrorum intimis, phyllariis exteri-

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Yuichi Kadota

Fig. 1. Type specimen of Cirsium myokoense Kadota (JAPAN: HONSHU; Niigata Pref., Myôkô-shi,
Sasagamine, alt. 1290 m, 17 September 2007, Y. Kadota 075103, TNS 769885, holotype).

Two new species of Cirsium from Honshu

nis involucrorum longioribus.
TYPE: JAPAN: HONSHU; Niigata Pref.,Myôkô-shi (former Naka-Kubiki-gun, MyôkôKôgen-cho), Sasagamine, at the foot of Mt.
Myôkô-san [36°5215N 138°0423E], alt. 1290m, 17 September 2007, Y. Kadota 075103 (TNS
769885–holotype; Fig. 1).
A hermaphrodite, perennial, herbaceous plant,
1–2 m tall or taller. Rootstock stout, horizontal,
up to 5 cm in diameter, with cord-like roots. Stemdeclining, well branched from the middle part,leafy, arachnoid and covered with short brownish
hairs chiefly in the upper part. Basal leaves withering at anthesis. Middle cauline leaves dull
green on the adaxial side, membranous, neither
auriculate nor amplexicaul, short petiolate;blades narrowly ovate to lanceolate in outline,
15–35 cm, 4–18 cm broad, glabrous on the adaxial side and sparingly pubescent with long brownish hairs along midribs on the abaxial side, shallowly to medially pinnatilobate or frequently

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coarsely dentate, if pinnatilobate, 5–8-jugate;
lobes narrowly ovate, 2–7 cm long, 1–2.5 cm
broad, with weak spines 1–3 mm long; petioles
0.3–1 cm long. Upper cauline leaves coarsely
dentate, subsessile. Flowers in September. Capitula 2–3 in a loose raceme, nodding, with peduncles 4–7 cm long; subtending leaves 2–5, lanceolate to narrowly ovate, 0.5–1 cm long, with sharp
spines ca. 1 mm long. Involucres cylindrical,
18–20 mm long, 8–10 mm (in vivo) and 2–3 cm(in sicco) in diameter, sparingly arachnoid. Phyllaries 9–10-seriate, patent to gently recurved;
glandular bodies absent, eglutinous; middle phyllaries sometimes provided with spinules along
the margin; outer phyllaries ovate with longacuminate tips, 5–8 mm long, clearly shorter than
the inner ones, herbaceous, terminated withsharp spines ca. 1 mm long. Corollae pale violet,
14–15 mm long; lobes 3–4 mm long; throats
4.5–5 mm long; tubes 6 mm long, slightly longer
than the throats. Achenes grayish brown, ca.

Fig. 2. Habit of Cirsium myokoense Kadota (JAPAN: HONSHU; Niigata Pref., Myôkô-shi, Sasagamine, alt.
1290 m, 17 September 2007). Left corner inset shows a nodding capitulum.

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Yuichi Kadota

3.5 mm long, ribbed; pappus sordid, 8–13 mm
long.
Chromosome number: 2n2x34.
Japanese name: Myôkô-azami (nom. nov.).
Distribution: Honshu (the Kubiki Mountain
Range, Myôkô Mountains; Fig. 5, star). Endemic
to Japan.
Additional specimens examined: JAPAN:
HONSHU; Niigata Pref., Naka-Kubiki-gun,
Myôkô-Kôgen-cho, Sasagamine, alt. 1400 m, 28
Sept. 2002, Y. Kadota 203017–203025 (TNS
730703–730710, 730741–730742); Myôkô-shi,
Sasagamine, at the foot of Mt. Myôkô-san[36°5215N 138°0423E], alt. 1290 m, 17 September 2007, Y. Kadota 075101–075102 (TNS
769883–769884).
Cirsium myokoense is distinguished from C.
tenuipedunculatum Kadota [ C. effusum auct.
non (Maxim.) Matsum.: cf. Kadota, 1993] byhaving cylindrical and thicker involucres, patent(spreading) and longer involucral phyllaries,
longer and thicker peduncles, membranous,
ovate, medially pinnatilobate cauline leaves
and the absence of glandular bodies on innerand middle involucral phyllaries. Cirsium
tenuipedunculatum is known as a member of the
Fossa Magna (Fuji–Hakone) Elements plants andis distributed in Mt. Fuji and its neighboring area
and the northern part of the Akaishi Mountain
Range.
Cirsium myokoense is different from C. horiianum Kadota by having longer peduncles, cylindrical involucres, patent (spreading) involucral
phyllaries, shorter florets and shorter, ribbed achenes. Cirsium horiianum is restricted to the Oga
Mountains, Akita Pref., northern Honshu. The
locality of C. horiianum is distant from that of C.
myokoense by ca. 400 km in beeline distance(Kadota, 2005).
Cirsium myokoense grows exclusively along
the margin of Fagus crenata woods. The range of
C. myokosense is restricted to the southern slopesof the Myôkô Mountains, central Honshu, Japan(Fig. 5, star).

2.

Cirsium nagisoense Kadota, sp. nov.
[Figs. 3, 4 and 6A]
Differt ab Cirsio furusei, foliis caulibus subter
glaucis (non lanatis), phyllariis involucrorum adpressis integris (sine spinulis), vittis bene evolutis oblongis vel oblanceolatis.
TYPE: JAPAN: HONSHU; Nagano Pref.,Kiso-gun, Nagiso-machi, Azuma, Araragi, atthe foot of Mt. Nagiso-dake, 35°3431N
137°3812, alt. 990 m, 20 September 2007, Y.
Kadota 075401 (TNS 769879–holotype; Fig. 3).
A hermaphrodite, perennial, herbaceous plant,
0.7–2 m high. Root stock sturdy, oblique tosuberect, up to 2 cm in diameter, with firm, cordlike roots. Stem erect to inclining, sulcate, wellbranched from the middle part, sparingly arachnoid and densely covered with multicellular,
brownish hairs throughout the surface; branches
well elongated. Basal leaves withering at anthesis. Middle cauline leaves deep green, herbaceous; blades narrowly ovate in outline,
16–35 cm long, 5–15 cm wide, glaucous on theabaxial side, almost glabrous on both sides,
deeply pinnatilobate, sessile, amplexicaul, notdeccurent; lobes 6–11-jugate, ovate, 2.5–7 cm
long, 0.7–1.5 cm wide, with strong and sharp
spines up to 10 mm long. Upper cauline leaves
narrowly ovate, smaller than the middle, diminishing in size, glabrous, sessile, amplexicaul.
Flowers in September to October. Capitula nodding, 3–4 in a loose corymb or solitary, long pedunculate; peduncles 6–17 cm long, densely pubescent with multicellular, brownish hairs; subtending leaves 3–5, lanceolate, 2–4 mm long,provided with weak spines less than 1 mm long.
Involucres narrowly cylindrical, exceedingly
glutinous, 13–15 mm long, 5–8 mm (in vivo) and
1–1.5 cm (in sicco) in diameter, sparingly arachnoid. Phyllaries 9–10-seriate, herbaceous, terminated with weak spines less than 1 mm long;
innermost phyllaries broadly linear, ca. 15 mm
long, erect; middle phyllaries narrowly ovate, ca.
1 cm long, adpressed; outer phyllaries ovate,adpressed, 2–4 mm long, 1/5 shorter than the
inner ones; glandular bodies well developed,
oblong to oblanceolate on all the phyllaries.

Two new species of Cirsium from Honshu

Fig. 3. Type specimen of Cirsium nagisoense Kadota (JAPAN: HONSHU; Nagano Pref., Kiso-gun, Nagisomachi, Azuma, Araragi, at the foot of Mt. Nagiso-dake, alt. 990 m, 20 September 2007, Y. Kadota 075401,
TNS 769879, holotype).

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Yuichi Kadota

Fig. 4. Habit of Cirsium nagisoense Kadota (JAPAN: HONSHU; Nagano Pref., Kiso-gun, Nagiso-machi,
Azuma, Araragi, at the foot of Mt. Nagiso-dake, alt. 990 m, 20 September 2007). Left corner inset shows a
nodding capitulum.

Two new species of Cirsium from Honshu

Fig. 5.

47

Distribution of Cirsium myokoense Kadota (star) and C. nagisoense Kadota (triangle).

Corollae violet to pale violet, 14–15 mm long;
lobes 2.5–4 mm long; throats 4.5–5 mm long;tubes 6–7 mm long, slightly longer than thethroats. Achenes grayish brown, minutely light
purple-spotted or -striated, ca. 3 mm long, angled, finely striate, tapered to the base; pappiivory-white, 8–13 mm long.
Chromosome number: 2n2x34.
Distribution: Central Honshu (Nagano Pref.,the southernmost part of the Kiso Mountain
Range; Fig. 5, triangle). Endemic to Japan.
Japanese name: Nagiso-azami (nom. nov.).
Additional specimens examined: JAPAN:
HONSHU; Nagano Pref., Kiso-gun, Nagisomachi, Azuma, Araragi, Mt. Nagiso-dake,alt. 950–1060 m, 30 Oct. 1997, Y. Kadota
978011–978021,
978030–978036(TNS
6510400–651400, 651392–651414); at the footof Mt. Nagiso-dake, alt. 900 m, 28 Oct. 1997, Y.
Kadota 978041–978045 (TNS 651423–651430);

at the foot of Mt. Nagiso-dake, 35°3431N
137°3812, alt. 990 m, 20 Sept. 2007, Y. Kadota
075402–075416 (TNS 769852–769870); Nagisomachi, Hirose, Chôjabata, alt. 1020 m, 29 Oct.
1997, Y. Kadota 978051–978059 (TNS 651616–
651620,651691–651699);
Nagiso-machi,
Hirose, Chôjabata Rindô [a forest road], alt.
1040 m, 29 Oct. 1997, Y. Kadota 978061–
978062 (TNS 651597–651603).
Cirsium nagisoense is distinguished from C.
furusei Kitam. (Fig. 6B) by cauline leaf bladesglaucous below (not woolly), adpressed, entire(not spinulose), involucral phyllaries, oblong tooblanceolate glandular bodies on the inner andmiddle involucral phyllaries.
Cirsium spinuliferum (Kitam.) Kadota, stat.
nov. [basionym: Cirsium kagamontanum Nakai
var. spinuliferum Kitam. in Mem. Coll. Sci.
Kyoto Imper. Univ., ser. B, 13: 99 (1937) – C.
furusei Kitam. var. spinuliferum (Kitam.) Kitam.

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Yuichi Kadota

Fig. 6. Comparison among Cirsium nagisoense Kadota, C. furusei Kitam. and C. spinuliferum (Kitam.) Kadota
in involucre. A. C. nagisoense (Nagano Pref., Kiso-gun, Nagiso-machi, Mt. Nagiso-dake). B. C. furusei(Nagano Pref., Kiso-gun, Ôkuwa-mura, Mt. Kosumo-yama). C. C. spinuliferum (Nagano Pref., Iida-shi, Mt.
Surikogi-yama).

in Satake et al., Wild Fl. Jap. Herb. Pl. III: 218(1981), comb. nud. TYPE: JAPAN: Honshu;
Prov. Shinano [Nagano Pref.], Mt. Koma
[Mt. Kiso-Komagatake], 28 Aug. 1936, G.
Koidzumi s.n. (holotype–KYO !); Fig. 6C] is discriminated from C. nagisoense by having cylindrical involucres and shortly recurved, spinulose
involucral phyllaries. Cirsium spinuliferum is distributed in the southeastern part of the Kiso
Mountain Range.
Cirsium kisoense (T. Yamaz. et S. Asano)
Kadota, stat. nov. [basionym: Cirsium norikurense Nakai var. kisoense T. Yamaz. et S.
Asano in J. Jpn. Bot. 40: 5, fig. 5 (1965). TYPE:
JAPAN: Honshu; Nagano Pref., Shimoina-gun,
Iida [Iida-shi], Mt. Nenzyo [Mt. Nenjô-dake],
Kamimatsukawa, alt. 1600 m, 12 Aug. 1963, T.
Yamazaki and S. Asano 7580 (holotype–TI !)] isdifferent from C. nagisoense by having cauline
leaf blades densely woolly on the abaxial side
and long and strongly recurved, spinulose involucral phyllaries. Cirsium kisoense is distributed on
the eastern foot of the Kiso Mountain Range andthe southern foot of Mts. On-take, Nagano Pref.,Honshu.
Cirsium nagisoense is restricted to the southern slopes of Mt. Nagiso-dake, Nagano Pref.,Honshu (Fig. 5, triangle), and grows near streams
along summer-green woods and/or Cryptomeria
japonica plantations.
Acknowledgement
I wish to give my sincere thanks to Prof. Dr. T.
Nishikawa for his counting the chromosome
numbers of Cirsium myokoense and C. nagisoense.
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