Botanical Studies (2009) 50: 107-113.

*

Corresponding author: E-mail: qeyang@scib.ac.cn; Tel:

86-20-37094273.

INTRODUCTION

Sinosenecio B. Nord. (Senecioneae-Asteraceae) is

a genus of ca. 38 species, all of which occur in China,

Indochina, and Korea (Jeffrey and Chen, 1984; Janovec

and Barkley, 1996; Chen, 1999; Liu, 2000; Zhang et al.,

2008), except for one species, S. newcombei (Greene)

J. P. Janovec & T. M. Barkley, disjunctly distributed in

the Queen Charlotte Islands, British Columbia, Canada

(Janovec and Barkley, 1996). The genus is characterized

by usually palmately veined, petiolate leaves with the

lamina distinct from the petiole,

ecalyculate involucres, a

campanulate limb of the disc florets, the polarized or

radial

pattern of the anther endothecial cell thickenings, and a

filament collar with uniformly sized cells (Nordenstam,

1978; Jeffrey and Chen, 1984). China, where 37 species

have been recorded (Chen, 1999; Liu, 2000;

Zhang et

al., 2008), is undoubtedly the most important center of

differentiation for the genus. It is noteworthy that most

species of Sinosenecio in China have a rather narrow

distribution, and thus, as pointed out by Jeffrey and Chen

(1984), discovery of new species is expected as botanical

exploration proceeds in this country.

For the first author¡¦s Ph.D. project on the systematics

and evolution of the genus Sinosenecio, we carried out

a botanical expedition throughout central and western

China from April to July, 2007. In northwestern Hunan,

in a valley near Mt. Ludong, Baojing Xian, we collected

plants similar to S. euosmus (Hand.-Mazz.) B. Nord. and S.

denticulatus J. Q. Liu, but which differed by having larger,

ovate-cordate, undivided leaves and basally expanded

but never auriculate petioles. We determined that they

represent an undescribed species, which is here described.

Sinosenecio baojingensis Y. Liu & Q. E. Yang, sp. nov.¡X

TYPE: CHINA: Hunan,

Baojing County, Mt. Ludong,

270 m, grassy places, 3 April 2007, Q. E. Yang, Qiong

Yuan & Ying Liu 554 (holotype, PE). «O¹t

»Z¨à®Ú

Figures 1, 2

Species nova haec similis

Sinosenecioni euosmo

(Hand.-Mazz.) B. Nord. et S. denticulato J. Q. Liu caule

foliato, acheniis laevibus pappo praeditis, ab illo planta

multo altiore, 75-150 cm alta, foliorum laminis multo

majoribus, 12-20 cm longis, 10-18 cm latis, ab hoc planta

vulgo altiore, foliorum laminis multo majoribus, ab

ambobus foliis indivisis, ambitu ovato-cordatis, petiolis

tantum basi dilatatis, haud auriculatis differt.

Herbs,

rhizomatous, stolons absent. Stem solitary,

erect, 75-150 cm tall, ca. 15-20 mm in diam. at base,

Sinosenecio baojingensis (Asteraceae), a new species

from Hunan, China

Ying LIU

1

, Gong-Xi CHEN

2

, and Qin-Er YANG

3,

*

1

State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing

100093, China

2

College of Biology and Environmental Science, Jishou University, Hunan 416000, China

3

South China Botanical Garden, Chinese Academy of Sciences, Xingke Road, Tianhe District, Guangzhou 510650, China

(Received March 18, 2008; Accepted November 7, 2008)

ABSTRACT.

Sinosenecio baojingensis Y. Liu & Q. E. Yang, a new species of Asteraceae from northwestern

Hunan, China, is described and illustrated. Its chromosome number (2n = 48) is reported here. The new

species is similar to S. euosmus and S. denticulatus in having leafy stems and smooth achenes bearing a

pappus. It differs from S. euosmus in its much taller stature (75-150 cm vs. 20-75 cm), the ovate-cordate

outline of its leaves (vs. ovate to broadly ovate), its denticulate (vs. crenate) margin, and its much larger size

(12-20 ¡Ñ 10-18 cm vs. 2-5 ¡Ñ 3-6 cm). From S. denticulatus it differs in its sometimes taller stature (75-150

cm vs. 35-140 cm), and ovate-cordate (vs. reniform) leaves, denticulate (vs. dentate) margin, and its larger

size (12-20 ¡Ñ 10-18 cm vs. 4-14 ¡Ñ 6-17 cm). From both it differs in having undivided (vs. more or less

lobed) leaves and basally expanded but never auriculate (vs. auriculate) petioles. A color plate, line drawings,

distribution map, light microscope (LM) photomicrographs of floral characters, and a key to aid in the

identification of S. baojingensis and its possible relatives are provided.

Keywords: Asteraceae; Chromosome number; Floral microcharacters; Senecioneae; Sinosenecio baojingensis.

TAxONOmy

108

Botanical Studies, Vol. 50, 2009

Figure 1. Sinosenecio baojingensis Y. Liu & Q. E. Yang. A, Habit; B, Phyllary; C, Ray floret; D, Disc floret; E, Stamen; F, Style-arms.

(All from Qin-er Yang et al. 554, PE).

LIU

et al. ¡X

Sinosenecio baojingensis

, a new species from China

109

Figure 2. Sinosenecio baojingensis Y. Liu & Q. E. Yang. A, Posture; B, Leaf; C, Inflorescence; D, Capitula; E, Florets. (All from Qin-

er Yang et al. 554, PE).

110

Botanical Studies, Vol. 50, 2009

simple, villous or lanate. Leaves radical and cauline.

Radical leaves petiolate; petioles 14-28 cm long, sparsely

lanate, base expanded; lamina ovate-cordate, 12-20

¡Ñ 10-18 cm, palmately veined, base cordate, margin

denticulate, apex acute, lower surface pale green or

whitish lanate, upper surface green and sparsely villous;

upper stem leaves smaller, with shorter petioles. Capitula

many, in apical compound corymbs; peduncles 1.5-4

cm long, sparsely villous. Involucres campanulate,

ecalyculate, 6-7 ¡Ñ 6-9 mm. Phyllaries ca. 13, uniseriate,

oblong-lanceolate, 6-7 ¡Ñ 1.5-2 mm, apex acuminate,

puberulous, herbaceous, green. Ray florets ca. 13; corolla

tube 3 mm long, glabrous; rays yellow, oblong-elliptic, ca.

8 mm ¡Ñ 3-4 mm, apically 3-denticulate, 4-7-veined. Disc

florets many; corolla 5 mm long, tube 3 mm long, limb

campanulate; lobes ovate-lanceolate. Anthers ca. 1.5 mm

long, base obtuse, appendages ovate-oblong. Style arms

ca. 1 mm long, apex truncate. Achenes cylindrical, 1.5 mm

long, smooth, glabrous. Pappus white, 3 mm long.

Additional specimens examined. CHINA. Hunan,

Baojing Xian, Mt. Ludong, in valley, 3 April 2007, Dai-

gui Zhang & Liang Xu 070403017 (JIU).

Etymology. The specific epithet ¡¥baojingensis¡¦ i s

derived from the type locality, Baojing County, Hunan

Province, China.

Phenology. Flowering from March to April; fruiting

May.

Distribution, habitat and status. Sinosenecio

baojingensis is known from only one population

in a

valley in Baojing Xian, Hunan, China (Figure 3), growing

in deep grass near paddyfields on an open hillside at an

altitude of ca. 270 m. If this is truly the only population,

then according to the IUCN red list categories and

criteria, version 3.1 (IUCN, 2001), S. baojingensis should

be categorized as a critically endangered species (CR).

Because the site is within an area of human activity, the

most serious threat to the species¡¦ survival lies in the

potential habitat destruction through mining and farming.

Figu re 3. Distribution of Sinosenecio baojingens is

(¡¶)

in

Hunan Province, China.

LIU

et al. ¡X

Sinosenecio baojingensis

, a new species from China

111

Floral micromorphological characters. To observe

anther endothecial cell thickenings and the filament collar

o f Sinosenecio baojingensis, we boiled the heads in

distilled water for 3 min, and then fixed them in Carnoy¡¦

s solution (glacial acetic acid : absolute ethanol = 1: 3).

Mature disc florets were removed from the fixed heads

and transferred to 70% ethanol for 30 min., then to 99%

ethanol for 1 h before they were immersed in 5% NaOH

for 24 h. The anther tissue was isolated from the florets

on the slide, flooded with 50% glycerol and a cover

slip was applied. Samples were then examined at 200¡Ñ

(filament collar) and 400¡Ñ (endothecial cell thickenings)

magnification by light microscopy and photographed.

The anther endothecial cell thickenings of Sinosenecio

baojingensis are polar and radial (Figure 4A), conforming

to the results reported previously that endothecial cell

thickenings are strictly polar, polar and radial or radial in

other species of the genus (Jeffrey and Chen, 1984). As

shown in Figure 4B, the new species has uniformly sized

cells in the filament collar, which is one of the diagnostic

features of the genus Sinosenecio (Nordenstam, 1978;

Jeffrey and Chen, 1984).

Chromosome cytology. For chromosome counts, root

tips were pretreated with 0.1% colchicine for 3 h before

being fixed in Carnoy solution (glacial acetic acid :

absolute ethanol = 1: 3), then macerated in a 1:1 mixture

of 45% acetic and 1 N HCl at 60¢XC for 4 min, stained and

squashed in Carbol fuchsin.

The chromosome number of Sinosenecio baojingensis

was determined to be 2n = 48 (Figure 5). Since the basic

number of the genus is x = 12 (Liu, 1999; Zhang et al,

2008), S. baojingensis is a tetraploid. The chromosome

number of one of its possible relatives, S. sungpanensis, is

2n = 48 (unpublished data).

Sinosenecio baojingensis can be readily referred to

section Phyllocaulon C. Jeffrey & Y. L. Chen subsection

Madarogyne C. Jeffrey & Y. L. Chen based on the

polar and radial pattern of the anther endothecial cell

thickenings, the presence of cauline leaves, and the

glabrous ovaries and achenes. As shown in Table 1, S.

baojingensis is similar to S. euosmus and S. denticulatus

within the subsection in having leafy stems and smooth

achenes bearing a pappus, but differs from the former in

its taller stature (75-150 cm vs. 20-75 cm), leaves ovate-

cordate in outline (vs. ovate to broadly ovate), margin

denticulate (vs. crenate), and much larger size (12-20

¡Ñ 10-18 cm vs. 2-5 ¡Ñ 3-6 cm). From S. denticulatus it

differs in having sometimes

taller stature (75-150 cm

vs. 35-140 cm),

and

leaves ovate-cordate in outline (vs.

reniform), margin denticulate (vs. dentate), and larger

size (12-20 ¡Ñ 10-18 cm vs. 4-14

¡Ñ

6-17 cm). From both

it differs in having undivided (vs. more or less lobed)

leaves and basally expanded but never auriculate (vs.

auriculate) petioles. Sinosenecio baojingensis is also

somewhat similar to two additional species in subsection

Madarogyne, S. sungpanensis (Hand.-Mazz.) B. Nord. and

Figure 4. Endothecial cell thickenings (A) and filament collars (B) of Sinosenecio baojingens is . A. Predominantly polarized

thickenings; B, Uniformly sized cells. (All from Qin-er Yang et al. 554, PE).

112

Botanical Studies, Vol. 50, 2009

S. fangianus Y. L. Chen, in the basally expanded petioles,

leafy stems, and achenes bearing a pappus, but differs in

leaf shape (ovate-cordate, undivded vs. reniform, lobed),

and achene surface (smooth vs. papillate). The five species

mentioned above can be distinguished by features in the

following key.

Key to Sinosenecio baojingensis and its related

species

1. Base of petioles auriculate.

2.

Leaves ovate to broadly ovate, margin shallowly to

deeply mucronulate-dentate .....................S. euosmus

2.

Leaves reniform, margin rather regularly

mucronulate-denticulate ......................S. denticulatus

1. Base of petioles expanded but never auriculate.

3.

Plants to 150 cm tall; leaves 12-20 ¡Ñ 10-18 cm,

ovate-cordate, undivided; achenes smooth ..............

...........................................................S. baojingensis

3.

Plants less than 100 cm; leaves less than 7 ¡Ñ 7 cm,

reniform, lobed; achenes papillate.

4.

Leaves shallowly 5-7-lobed; base of petioles

obviously expanded¡K¡K.......¡K¡KS. sungpanensis

4.

Leaves palmately 7-9-fid; base of petioles slightly

expanded ¡K....................................¡K S. fangianus

Acknowledgments. We are very grateful to Dr. Bertil

Nordenstam and two other anonymous referees for their

invaluable comments on the manuscript. We thank Mr. Sun

Ying-bao for the drawing. This work was supported by the

National Natural Science of Foundation of China (Grant

no. 30770157), and the Knowledge Innovation Project of

the Chinese Academy of Sciences (KZCX2-YW-415).

LITERATURE CITED

Chen, Y.L. 1999. Sinosenecio B. Nord. In Anonymous (ed.),

Flora Reipublicae Popularis Sinicae 77(1). Science Press,

Beijing, pp. 101-141.

IUCN. 2001. IUCN Red list categories ad criteria, v.3.1. Gland/

Cambridge: IUCN Species Survival Commission.

Janovec, J.P. and T.M. Barkley. 1996. Sinosenecio newcombei

(Asteraceae: Senecioneae): a new combination for a North

American plant in an Asiatic genus. Novon 6: 265-267.

Jeffrey, C. and Y.L. Chen. 1984. Taxonomic studies on the tribe

Senecioneae (Compositae) in the eastern Asia. Kew Bull.

39: 205-446.

Liu, J.Q. 1999. Systematics of the Tribe Senecioneae Subtribe

Tuss ila gininae (As teraceae ) of the Eastern Asia. P h.D.

thesis, Institute of Botany, Chinese Academy of Sciences,

Beijing.

Liu, J.Q. 2000. A new species of Sinosenecio B. Nord.

(Asteraceae, Senecioneae). Acta Phytotax. Sin. 38: 192-194.

Nordenstam, B. 1978. Taxonomic studies on the tribe

Senecioneae (Compositae). Opera Bot. 44: 1-84.

Zhang, D.G., Y. Liu, and Q.E. Yang. 2008. Sinosenecio

jishouensis (As teraceae), a new species from north-wes t

Hunan, China. Bot. Stud. 49: 287-294.

Figure 5. Interphase nuclei (A), mitotic prophase (B), and metaphase (C, 2n = 48) chromosomes of Sinosenecio baojingensis. (All

from Qin-er Yang et al. 554, PE).

LIU

et al. ¡X

Sinosenecio baojingensis

, a new species from China

113