Bull. Natl. Mus. Nat. Sci., Ser. B, 35(4), pp. 189–203, December 22, 2009

Taxonomic Studies of Cirsium (Asteraceae) in Japan XXI.
Four 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 Three new species (Cirsium akimontanum, C. nagatoense and C. yuzawae) of subsect.
Reflexae and a new species (C. yamauchii) of subsect. Tubelosae are described from Honshu,
Japan, within sect. Onotrophe of the genus Cirsium. Cirsium akimontanum Kadota described from
Yamaguchi, Hiroshima and Shimane Prefs. is distinguished from C. kagamontanum Nakai by having subcoriaceous cauline leaves, short and thick peduncles, ascending involucral phyllaries andlanceolate glandular bodies. Cirsium nagatoense Kadota described from the western part of Yamaguchi Pref. is characterized by having thick and coriaceous cauline leaves and the lowest elevationof habitats among the species of subsect. Reflexae (the Cirsium kagamontanum group). Cirsium
yuzawae Kadota described Fukushima Pref. is characterized by patent and/or recurved involucral
phyllaries and the absence of glandular bodies. Cirsium yamauchii Kadota also described from
Fukushima Pref. is a coastal plant and is unique in having lustrous, coriaceous cauline leaves.
Key words : Cirsium akimontanum, Cirsium nagatoense, Cirsium yamauchii, Cirsium yuzawae,
Japan, new species.

Introduction
This is part of a revisional work on JapaneseCirsium (Asteraceae) (Kadota, 1989–2009; Kadota and Nagase, 1988).
During the course of systematic studies on
Japanese Cirsium three entities within the subsect. Reflexae of sect. Onotrophe (Cass.) DC.
were found in Fukushima, Shimane, Hiroshima
Prefs., Honshu in October of 1998. Since thenfield and herbarium observations have been done
for more than ten years. As a result these three
entities will be described as new species; Cirsium
yuzawae Kadota from Fukushima Pref., C. akimontanum Kadota from Shimane, Hiroshima andthe eastern part of Yamaguchi Pref. and C. nagatoense Kadota from the western part of Yamaguchi Pref.
In November of 2008 a curious thistle wasfound at the Hattachi Kaigan [coast], Iwaki,
Fukushima Pref., northern Honshu. Based onfield survey conducted in October of 2009 as

well as specimen examinations of herbarium
materials it turned out that this thistle is ascribable to a new species of sect. Onotrophe subsect.
Tubelosae Kitam. This thistle will be also described here as Cirsium yamauchii after the discoverer of this new species.

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.-Petersb. 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.

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Yuichi Kadota

Geobot. 3: 5 (1934), p. p.
1.

Cirsium akimontanum Kadota, sp. nov.
[Figs. 1–2]
Differt ab Cirsio kagamontano, foliis caulinis
subcoreaceis, pedunculis brevioribus et crassioribus, phyllariis involucrorum ascendentibus,
vitiis lanceolatis.
TYPE: JAPAN: HONSHU; Hiroshima Pref.,Hatsukaichi-shi, Yoshiwa, Nakatsu-dani Gorge
37°1559.4N 140°5417.9E, alt. 235 m, 14 Oct.
2009, Y. Kadota 097307 (TNS 742927–742928–
holotype; Fig. 1).
A hermaphrodite, perennial, herbaceous plant,
1–2.5 m tall or taller. Rootstock stout, horizontal,
up to 5 cm in diameter, with cord-like roots. Stemdeclining to suberect, well branched from the
middle part, leafy, sparingly arachnoid and covered with short brownish hairs chiefly in theupper part. Basal leaves withering at anthesis.
Lower cauline leaves dark yellowish green on the
adaxial side, membranous, amplexicaul, auriculate, sessile; blades narrowly ovate to narrowly
elliptic in outline, 20–42 cm, 6–18 cm broad, almost glabrous on both sides, shallowly pinnatilobate, 5–7-jugate; lobes ovate, 2.5–9 cm long,
1–3 cm broad, spreading, with weak spines
2–4 mm long. Middle and upper cauline leaves
shallowly pinnatilobate to coarsely dentate, sessile. Flowers in September to October. Capitula
2–4 in a raceme, nodding, with peduncles
0.5–3 cm long; subtending leaves 3–5, ovate tolinear, 1–3 mm long, with weak spines less than
1 mm long. Involucres narrowly cylindrical,
11–16 mm long, 5–6 mm (in vivo) and 1–1.5 cm(in sicco) in diameter, sparingly arachnoid. Phyllaries 11–12-seriate, adpressed; glandular bodies
elliptic, glutinous or sometimes eglutinous; innermost phyllaries narrowly obovato-lanceolate,ca. 15 mm long; outer phyllaries ovate withacuminate tips, ca. 2 mm long, clearly shorter
than the inner ones, herbaceous, terminated withweak spines ca. 1 mm long. Corollae pale pink,
16–18 mm long; lobes 4–5 mm long; throats
4–6 mm long; tubes 7 mm long, slightly longer
than the throats. Achenes brownish gray to gray-ish ivory-white, 3 mm long, ribbed; pappus
sordid, 10–14 mm long.
Chromosome number: 2n2x34 (present
paper).
Japanese name: Geihoku-azami (nom. nov.).
Distribution: Western Honshu (Shimane,
Hiroshima and Yamaguchi Prefs.). Endemic toJapan.
Etymology: The specific epithet “akimontanum” is derived from the name of the westernpart of Hiroshima Prefecture, western Honshu,
Japan.
Additional specimens examined: JAPAN:
HONSHU; Hiroshima Pref., Hatsukaichi-shi,
Yoshiwa, Nakatsu-dani Gorge, alt. 750 m, 23 Oct.
2008, Y. Kadota 088534 (TNS 777145–777146).
Shimane Pref., Kanoashi-gun, Nichihara-cho,
Mt. Azoji-san, Okudani, alt. 740 m, 11 Oct.
2000, Y. Kadota 203061–203065, 203120–
203123 (TNS 704447–704450, 704452–704456).
Mino-gun, Hikimi-cho, Mt. Osorakan-san,Kameidani, alt. 500 m, 13 Oct. 2000, Y. Kadota
203107–203112 (TNS 704236–704242); Hikimicho, Nanamura, alt. 960 m, 12 Oct. 2000, Y.
Kadota 203068–203072 (TNS 704574–704583).
Cirsium akimontanum is discriminated fromC. kagamontanum by having subcoriaceous
leaves, short and thick peduncles, ascending involucral phyllaries and lanceolate glandular
bodies (Fig. 2).
Cirsium akimontanum grows abundantly along
the margin of summer-green woods in the montane zone, Yamaguchi (eastern part), Hiroshima
and Shimane Prefs.
2.

Cirsium nagatoense Kadota, sp. nov.
[Figs. 3–4]
Differt ab Cirsio akimontano, foliis coriaceis,
phyllariis involucrorum adpressis.
TYPE: JAPAN: HONSHU; Yamaguchi
Pref., Hagi-shi, Kawakami, Shimo-Sasao,
37°1929.8N 131°2924.2E, alt. 250 m, 23 Oct.
2008, Y. Kadota 088530 (TNS 777195–holotype;Fig. 3).
A hermaphrodite, perennial, herbaceous plant,
0.7–2 m tall. Rootstock stout, horizontal, up toFour New Cirsium Species from Honshu

191

Fig. 1. Type specimen of Cirsium akimontanum Kadota (JAPAN: HONSHU; Hiroshima Pref., Hatsukaichi-shi,
Yoshiwa, Nakatsudani-gawa Gorge, alt. 282 m, 14 Oct. 2009, Y. Kadota 097307, TNS 742927).

Fig. 2. Habit of Cirsium akimontanum Kadota (JAPAN: HONSHU; Hiroshima Pref., Hatsukaichi-shi, Yoshiwa, Nakatsudani-gawa Gorge, alt. 890 m, 14 Oct. 2009).
Right corner inset shows nodding capitulum.

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Four New Cirsium Species from Honshu

193

Fig. 3. Type specimen of Cirsium nagatoense Kadota (JAPAN: HONSHU; Yamaguchi Pref., Hagi-shi,
Kawakami, Shimo-Sasao, alt. 250 m, 23 Oct. 2008, Y. Kadota 088530, TNS 777195).

Fig. 4. Habit of Cirsium nagatoense Kadota (JAPAN: HONSHU; Yamaguchi Pref., Hagi-shi, Kawakami, Shimo-Sasao, alt. 250 m, 23 Oct. 2008). Right corner inset
shows nodding capitulum.

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Four New Cirsium Species from Honshu

3 cm in diameter, with cord-like roots. Stemsuberect to declining, well branched from the
middle part, leafy, sparingly arachnoid and covered with short brownish hairs chiefly in theupper part. Basal leaves withering at anthesis.
Lower cauline leaves deep green on the adaxialside, coriaceous, amplexicaul, auriculate, sessile;blades narrowly ovate in outline, 15–35 cm,
5–12 cm broad, almost glabrous on both sides,
medially to shallowly pinnatilobate, 6–8-jugate;
lobes ovate, 2–3 cm long, 1–2 cm broad, spreading, with strong spines 4–7 mm long, porrect.
Middle and upper cauline leaves pinnatilobate tocoarsely dentate, sessile. Flowers in October toNovember. Capitula 2–3 in a raceme or solitary,
nodding, with peduncles (0–)2–15 mm long; subtending leaves 3–5, narrowly ovato-lanceolate tolinear, 3–10 mm long, with sharp spines ca. 1 mm
long. Involucres narrowly cylindrical, 15–17 mm
long, (5–)6 mm (in vivo) and 1–1.5 cm (in sicco)
in diameter, sparingly arachnoid. Phyllaries
11–12-seriate, adpressed; glandular bodies lanceolate, glutinous; innermost phyllaries narrowly

195

obovato-lanceolate, ca. 15 mm long; outer phyllaries broadly ovate with acute tips, ca. 3 mm
long, clearly shorter than the inner ones, subcoriaceous, terminated with sharp spines ca. 1 mm
long. Corollae pink to pale pink, 16 mm long;
lobes 3–4 mm long; throats 6 mm long; tubes
6–7 mm long, slightly longer than or as long as
the throats. Achenes brownish gray, 3 mm long,ribbed; pappus sordid, 9–12 mm long.
Chromosome number: 2n2x34 (present
paper).
Japanese name: Nagato-azami (nom. nov.).
Distribution: Western Honshu (the eastern partof Yamaguchi Pref.). Endemic to Japan.
Etymology: The specific epithet “nagatoense”
is derived from the old name of the western partof Yamaguchi Prefecture, western Honshu,
Japan.
Additional specimens examined: JAPAN:
HONSHU; Yamaguchi Pref., Hagi-shi, Kawakami, Shimo-Sasao, 37°1929.8N 131°2924.2E,
alt. 250 m, 23 Oct. 2008, Y. Kadota 088527–
088529, 088531 (TNS 777191–777192, 777196–

Fig. 5. Comparison in the shape of involucral phyllaries between Cirsium akimontanum (A) and C. nagatoense(B). A. JAPAN: HONSHU; Hiroshima Pref., Hatsukaichi-shi, Yoshiwa, Nakatsudani-gawa Gorge. B. JAPAN:
HONSHU; Yamaguchi Pref., Hagi-shi, Kawakami, Shimo-Sasao.

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Yuichi Kadota

777199).
Cirsium nagatoense (Fig. 4) is distinguishedfrom C. akimontanum by coriaceous leaves andadpressed involucral phyllaries. Cirsium nagatoense (Fig. 5B) is different from C. akimontanum (Fig. 5A) also in the shape of middle andouter involucral phyllaries (broadly ovate vs.
ovate). Glandular bodies of C. nagatoense arealways well developed and the involucres arestrongly glutinous while glandular bodies of
C. akimontanum are frequently degenerated.
The range of Cirsium nagatoense is geographically segregated from that of C. akimontanum: C.
nagatoense is distributed in the western half of
Yamaguchi Pref. whereas C. akimontanum is distributed in the eastern half of Yamaguchi Pref.,Hiroshima Pref. and the western half (Iwami
Prov.) of Shimane Pref. The localities of C. nagatoense is the lowest in elevation within the Cirsium kagamontanum group.
3.

Cirsium yuzawae Kadota, sp. nov.
[Figs. 6–7]
Differt ab Cirsio horiiano, phyllariis 11–12seriatis, foliis caulinis inferiis et mediis ovatis vel
late ovatis vel late ellipticis, pedunculis brevioribus et crassioribus, acheniis maginis; ab C.
tenuipedunculato, phyllariis 11–12-seriatis, caulebene ramoso ramis ascendentibus, flosculis brevioribus, pedunculis brevioribus et crassioribus,
acheniis minorioribus; ab C. myokoenso, phyllariis 11–12-seriatis, foliis caulinis inferiis etmediis profunde pinnatilobatis breviter petiolatis,
lobiis foliorum patentibus, phyllariis medioris etexterinis involucrorum longioribus et patentibus,
involucriis crassioribus.
TYPE: JAPAN: HONSHU; Fukushima Pref.,Futaba-gun, Naraha-machi, On’nadaira, Kidogawa Gorge, near the Kurihashi-bashi bridge
37°1559.4N 140°5417.9E, alt. 235 m, 4 Oct.
2009, Y. Kadota 096165 (TNS 742921–742926–
holotype; Fig. 6).
A hermaphrodite, perennial, herbaceous plant,
0.7–2.4 m tall or taller. Rootstock stout, horizontal, up to 3 cm in diameter, with cord-like roots.
Stem declining to suberect, well branched fromthe middle part, leafy, sparingly arachnoid andcovered with short brownish hairs chiefly in theupper part. Basal leaves withering at anthesis.
Lower cauline leaves deep green or sometimes
variegated on the adaxial side, membranous,
slightly amplexicaul, not auriculate, subsessile;blades ovate to broadly ovate or broadly elliptic
in outline, 22–40 cm, 6–28 cm broad, almost
glabrous on both sides, deeply pinnatilobate or
rarely subentire, if pinnatilobate, 5–7-jugate;
lobes narrowly ovate, 6.5–12 cm long, 3–8 cm
broad, spreading, with strong spines 5–10 mmlong, porrect. Middle and upper cauline leaves
pinnatilobate to coarsely dentate, subsessile or
short-petioled. Flowers in September to October.
Capitula 3–4 in a raceme or sometimes solitary,
nodding, with peduncles 1–6.5 cm long; subtending leaves 3–5, narrowly ovato-lanceolate, 0.5–
2.5 cm long, with sharp spines ca. 1 mm long.
Involucres narrowly cylindrical, ca. 16 mm long,
6–8 mm (in vivo) and 1.5–2 cm (in sicco) in
diameter, sparingly arachnoid. Phyllaries 11–12seriate, ascending to subpatent; glandular bodies
absent, eglutinous; innermost phyllaries narrowly
obovato-lanceolate, ca. 15 mm long; outer phyllaries ovate with acuminate tips, ca. 2 mm long,clearly shorter than the inner ones, herbaceous,terminated with sharp spines ca. 1 mm long.
Corollae pale pink, 17–20 mm long; lobes 4 mm
long; throats 5–6 mm long; tubes 8–10 mm long,clearly longer than the throats. Achenes grayish
ivory-white, 3.5–4 mm long, ribbed; pappus sordid, 11–15 mm long.
Chromosome number: 2n2x34 (present
paper).
Japanese name: Iwaki-hime-azami (nom. nov.).
Distribution: Honshu (the Abukuma Height,
Fukushima Pref.). Endemic to Japan.
Etymology: The specific epithet “yuzawae” isdedicated to Dr. Yôichi Yuzawa, Iwaki, Fukushima Pref., who devoted himself to survey thisnew thistle in Fukushima Pref., northern Honshu.
Additional specimens examined: JAPAN:
HONSHU; Fukushima Pref., Futaba-gun, Naraha-machi, Kido-gawa Gorge, alt. 320 m, 6 Oct.
1998, Y. Kadota 986062–986074 (TNS 676016–

Four New Cirsium Species from Honshu

197

Fig. 6. Type specimen of Cirsium yuzawae Kadota (JAPAN: HONSHU; Fukushima Pref., Futaba-gun, Narahamachi, On’nadaira, Kido-gawa Gorge, near the Kurihashi-bashi bridge, alt. 235 m, 4 Oct. 2009, Y. Kadota
096165, TNS 742921).

Fig. 7. Habit of Cirsium yuzawae Kadota (JAPAN: HONSHU; Fukushima Pref., Futaba-gun, Naraha-machi, On’nadaira, Kido-gawa Gorge, near the Kurihashi-bashi
bridge, alt. 235 m, 4 Oct. 2009). Right corner inset shows nodding capitulum.

198
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Four New Cirsium Species from Honshu

676031); Naraha-machi, On’nadaira, Kidogawa Gorge, near the Kurihashi-bashi bridge,
37°1559.4N 140°5417.9E, alt. 235 m, 4 Oct.
2009, Y. Kadota 096161–096164, 096166–
096170 (TNS); Naraha-machi, On’nadaira, near
Kido Dam, 37°1616.9N 140°5512.3E, alt.
165 m, 4 Oct. 2009, Y. Kadota 096141–096142,
096145–096149 (TNS). Iwaki-shi, Kawamaemachi, Onigajô, 28 Nov. 1997, E. Fukazawa
97004 (TNS 652813); Iwaki-shi, Tabito-machi,“Mizunomi-ba”, alt. 640 m, 4 Oct. 1998, Y.
Kadota 986020–986025 (TNS 675892–675899).
In the subsect. Reflexae (Kitam.) Kadota [theCirsium kagamontanum group] the following
three species are similar to C. yuzawae in having
eglutinous involucres and spreading and/or longrecurved involucral phyllaries; C. horiianum
Kadota, C. myokoense Kadota and C.
tenuipedunculatum Kadota. However, the three
species above-stated are easily distinguishedfrom C. yuzawae (Fig. 7) by having 9–10(–11)seriate involucral phyllaries.
Cirsium horiianum Kadota (2005) is discriminated from C. yuzawae by having ovate to obovate-elliptic cauline leaf blades, long and slenderpeduncles and larger achenes. Cirsium horiianum
is restricted to Oga Peninsula, Akita Pref., northern Honshu.
Cirsium myokoense Kadota (2009a) is different from C. yuzawae by having petiolate, shallowly pinnatilobate cauline leaves with ascending
lobes, longer and spreading involucral phyllaries
and thicker involucres. Cirsium myokoense isrestricted to Myôkô Mountains, Niigata Pref.,central Honshu.
Cirsium tenuipedunculatum Kadota (1997; C.
effusum auct. Jap. non (Maxim.) Matsum.) is discriminated from C. yuzawae by having divaricate
branches, shorter florets, and longer and slenderpeduncles. Cirsium tenuipedunculatum is distributed in the Fuji-Hakone Floral Region, the northernmost part of the Akaishi Mountain Range andthe Kanto Mountain Range (Chichibu Mountains), central Honshu.
In the vicinity of the type locality Cirsium
yuzawae grows along the margin of secondary

199

woods consisting Abies firma, Acer palmatum,
Euptelea polyandra, Carpinus tschonoskii, Sasa
borealis, Carpesium abrotanoides, Agastache rugosa and so on. This type of forests is ascribableto the medium-temperate forest on the Pacific
Ocean side of Tohoku District, northern Honshu.
Putative hybrids between Cirsium yuzawae andC. microspicatum were also found in the vicinityof the type locality, Kido Dam, Naraha-machi,
Futaba-gun, Fukushima Pref. (Kadota 096143–
096144). These hybrids are characterized by having subsessile heads, glutinous involucres andascending leaf lobes.
Subsect. Tubelosae Kitam. in Acta Phytotax.
Geobot. 3: 5 (1934), p.p.
TYPE: Cirsium suzukaense Kitam.
Ser. Imbricatae Kitam. in Acta Phytotax.
Geobot. 3: 5 (1934), p.p.
Ser. Refexae Kitam. in Acta Phytotax. Geobot.
3: 5 (1934), p.p.
4.

Cirsium yamauchii Kadota, sp. nov.
[Figs. 8–9]
Differt ab Cirsio takahashii, foliis caulinis
lucidis incrassatis scabris, absentia vittae, involucriis longioribus, pedunculiis brevioribus; ab C.
heiiano, foliis caulinis lucidis incrassatis scabris,absentia vittae, phyllariis involuclorum integris
late ovatis cum apivius caudatis longe recurvatis.
TYPE: JAPAN: HONSHU; Fukushima Pref.,Iwaki-shi, Hisanohama-machi, Hattachi Kaigan[beach], in coastal herb stand, 37°0707.3N
140°5958.2E, alt. 5 m, 3 Oct. 2009, Y. Kadota
096132 (TNS 741839–741842–holotype; Fig. 8,
hermaphrodite plant). Fukushima Pref., Iwakishi, Hisanohama-machi, Hattachi Kaigan, alt. ca.
5 m, 3 Oct. 2008, Y. Yuzawa and M. Yamauchi
23823 (TNS 779007–paratype; female plant).
A gynodioecious, perennial, herbaceous plant,
0.7–2 m high. Root stock stout, horizontal, up to
5 cm in diameter, with cord-like roots. Stem sulcate, declining to suberect, sparingly arachnoid,much branched from the middle part; branches
not elongated. Basal leaves withering at anthesis.
Middle cauline leaves deep green on the adaxial

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Yuichi Kadota

Fig. 8. Type specimen of Cirsium yamauchii Kadota (JAPAN: HONSHU; Fukushima Pref., Iwaki-shi,
Hisanohama-machi, Hattachi Kaigan, in coastal herb stand, alt. 5 m, 3 Oct. 2009, Y. Kadota 096132, TNS
741839).

Four New Cirsium Species from Honshu

side, glaucous on the abaxial side, coriaceousand scabrous, dimly lustrous, ovate to obovatoelliptic in outline, subentire (Fig. 9A) to coarsely
incised (Fig. 9B), 20–36 cm long, 8–19 cm wide,
provided with weak spines 2–5 mm long,glabrous on the adaxial side, sparingly arachnoid
and pubescent with multicellular brownish hairson the abaxial side, petiolate, not amplexicaul orsometimes semiamplexicaul, not deccurent; if incised, incisions 4–8-paired, triangular-ovate, 2–
3.5 cm long, 1–3 cm wide; petioles 0.5–6 cm
long, winged. Flowers in September to October.
Capitula erect to oblique, superficially nodding

201

when the stem falls down, 3–4 in a compact
corymb; peduncles (0–)2–5 mm long, arachnoid;
subtending leaves 2–5, linear to narrowly ovatolanceolate, 3–5 mm long, provided with weakspines ca. 1 mm long. Involucres narrowly cylindrical, eglutinous, 15–18 mm long, 7–8 mm (invivo) and 1.5–2 cm (in sicco) in diameter, sparingly arachnoid. Phyllaries 11–12(–13)-seriate,
chartaceous, terminated with weak spines ca.
0.5 mm long; glandular bodies absent; innermost
phyllaries narrowly obovato-lanceolate, ca. 15
mm long; outer phyllaries narrowly ovate withstrongly recurved caudate tips, 2–3 mm long.

Fig. 9. Habit of Cirsium yamauchii Kadota. A. Subentire-leaved plant. B. Coarsely serrate-leaved plant.
C. Female head. D. Hermaphrodite head. All photographed at Hattachi Kaigan, Hisanohama-machi, Iwakishi, Fukushima Pref., Japan, on 3 Oct. 2009.

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Yuichi Kadota

Corollae pale violet (Fig. 9D, hermaphrodite
plant) to deep pink (Fig. 9C, female plant), 13–
16 mm long; lobes 3–4 mm long; throats 4–6 mm
long; tubes 6 mm long, slightly longer than or as
long as the throats. Achenes ivory white tinged
with pale purplish brown, ca. 4 mm long, striate,not ribbed; pappi sordid, 9–13 mm long.
Chromosome number: 2n2x34 (present
paper).
Japanese name: Hattachi-azami (nom. nov.)
Distribution: Honshu (Hattachi beach, Iwaki,
Fukushima Pref.). Endemic to Japan.
Etymology: The specific epithet “yamauchii ”
is dedicated to Mr. Mikio Yamauchi, Iwaki,
Fukushima Pref., who is the discoverer of thisnew thistle.
Additional specimens examined: JAPAN:
HONSHU; Fukushima Pref., Iwaki-shi,
Hisanohama-machi, Hattachi Kaigan, in coastal
herb stand, 37°0707.3N 140°5958.2E, alt.
5 m, 3 Oct. 2009, Y. Kadota 096131, 096133–
096134*, 096135–096136, 096137–096138*(TNS); Hattachi Kaigan, in coastal herb stand,
37°0700.3N 140°5958.0E, alt. 7 m, 3 Oct.
2009, Y. Kadota 096111–096112, 906113*,
096114–096118, 096119–096121* (TNS). The
collection number attached with an asterisk “*”indicates female plant.
Cirsium yamauchii is a coastal plant and has
thick and lustrous leaves adapting to the coastal
climate. This thistle grows with Castanopsis
sieboldii, Pittosporum tobira, Fatsia japonica,
Elaeagnus macrophylla, Farfugium japonicum,
Miscanthus sinensis, Cyrtomium fortunei etc.
The habitats are located close to the sea shore
and are easily washed over by waves in stormy
weather. Whereas the other species of the subsect. Tubelosae occur in inland regions of Honshu and Hokkaido. Cirsium yamauchii is characteristic of its habitat preference in this subsection.
Acknowledgements
I am deeply indebted to Dr. Y. Yuzawa for his
field examination to Cirsium yuzawae; Mr. M.

Yamauchi for detailed information of Cirsium
yamauchii; Dr. M. Kubota for C. akimontanum.
My thanks also go to Messrs. T. Saito, K. Hasunuma and Ms. E. Fukazawa for their kind help
to my field studies in the localities of Cirsium
and useful information on these thistles. I wish to
give my sincere thanks to Prof. Dr. T. Nishikawa
for his counting the chromosome numbers of
Cirsium yamauchii.
References
Kadota, Y. 1989. Genus Cirsium. In: Ono, M., Ohba, H.
and Nishida, M. (eds.), Makino’s New Illustrated Floraof Japan. pp. 799–807. Hokuryukan, Tokyo (in Japanese).
Kadota, Y. 1990. Taxonomy and distribution of Cirsium
brevicaule A. Gray and its related species (Asteraceae).
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