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Tylophora sui (Asclepiadaceae: Marsdenieae), a New Species from

Coral Reef Areas in Hengchun Peninsula, Taiwan

Yen-Hsueh Tseng1,2, Chien-Ti Chao 1, Hui-Wen Lin 1

1. Department of Forestry, National Chung-Hsing University, 250 Kuo-Kuang Rd., Taichung 402, Taiwan.

2. Corresponding author. E-mail:tseng2005@nchu.edu.tw

ABSTRACT. Tylophora sui Y. H. Tseng & C. T. Chao, a new species of Asclepiadaceae from coral reef areas

in southern Taiwan, is described and illustrated. It resembles T. ovata (Lindl.) Hook. ex Steud. in the shape and

size of the leaves and flowers, but differs in the creeping stems, indumentum of stems, glabrous upper surface

of leaves and short inflorecence. According to the IUCN Red List Categories and Criteria this species is treated

as vulnerable (VU), since it is known only from southern Taiwan, and its habitats are easily disturbed by

human activities.

Key words: Asclepiadaceae; Tylophora sui; new species; Taiwan; Plant taxonomy.

INTRODUCTION

The genus Tylophora R. Brown (Asclepiadaceae) comprises 60 species that are mainly

distributed in tropical and subtropical Asia, Africa, and Australia. A total of 35 species has been

found in China (Li, et al., 1995). Two taxa of Tylophora were previously recognized in the Flora of

Taiwan (Lu & Kao, 1978). Recently, three taxa were recognized in the second edition of Flora of

Taiwan (Lu et al., 1998). In our recent systematic revision of Tylophora of Taiwan, one sharply

distinct species was discovered. Consultation of original materials and the recent monograph on

Tylophora (Henry, 1896; Kawakami, 1910; Hayata, 1911; Sasaki, 1928; Masamune, 1954;

Hatusima, 1963; Tsiang and Li, 1974; Lu and Kao, 1978; Lu et al., 1998) and relevant literature

from nearby regions (Li et al., 1995; Forster, 1992; Swarupanandan and Nicolson, 1993; Forster,

1994 ; Yamashiro et al., 2002) supports its recognition as a new species.

NEW SPECIES

Tylophora sui Y. H. Tseng & C. T. Chao , sp. nov. －TYPE: Taiwan. Pintung (County), Hengchun

(Town), Longpan, coral reef areas near seashore,120o 51’ 14.25” E, 21o 55’ 20.6” N, elev. ca. 76 m,

25 May 2009,Yen-Hsueh Tseng 4668 (holotype, TCF). 蘇氏鷗蔓 Figures1, 2

Planta repens. Caules villosi. Folia orbicularia, supra glabra, subtus margineque villosa, venis

prominentibus. Corolla utrinque glabra. Pollinia 2 in quoque pollinario, candicula horizontali,

retinaculo elliptico, apice obtuso.

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Plants creeping. Stems villous. Leaves simple, opposite, entire, fleshy; petiole 0.5-1.3 cm long,

villous, grooved; blade 2-3 by 1.5-2.5 cm, orbicular, adaxial surface glabrous, veins prominent,

lateral veins 3-4 pairs, margin and abaxial surface villous; apex mucronate; base cordate; Cymes

axillary, simple or 2; peduncles sparsely pubescent to glabescent, 2-2.5 cm long, rachis 1-8 mm

long, branched zigzag; bracteoles 1 at the base of each flower, lanceolate, hirsute; pedicels glabrous,

5-12 mm; calyx glabrous but sparsely hirsute at apex, 5-lobed, lobes broadly triangular; corolla

rotate, 5-lobed, glabrous on both surfaces, ovate, fleshy; corona 5-lobed, lobes with fleshy

tumor-like appendages outside; gynostegium cylindraceous, pollinarium 5, pollinia 2 per

pollinarium, candicule horizontal, retinaculum elliptic and apically obtuse; stigma disciform, style

cylindraceous, ovaries glabrous. Follicles 2 per pedicel, spindle lanceolate, obtuse at apex, 3-4.5 cm

long, 0.7-1.0 cm broad. Seed teapot-like, circular winged, glabrous, 0.4-0.6 cm long, 0.1- 0.2 cm

broad..

Additional. Specimens Examined. TAIWAN. Pingtung (County), Hengchun (Town), Longpan,

coral reef areas near seashore, elev. ca. 60 m, 10 Sep. 2009,Yen-Hsueh Tseng 4803 (paratype,

TCF).

Etymology: The specific epithet commemorates Prof. Horng-Jye Su, the mentor of the senior

author, School of Forestry and Resource Conservation, National Taiwan University, for his

contributions to plant taxonomy and vegetation ecology of Taiwan.

Material and method of Chromosome observation: The method is according to Yamashiro et al.

(2002). The root tips were collected in sunny day morning, about 9:00 am to 12:00 p.m.. Root tips

were pretreated in 2mM 8-hydroxyquinoline for 8-12 hours. The root tips were fixed in Carnoy’s

solution (acetic acid: absolute ethanol = 1:3, v:v) for 8-12 hours under 4℃. After squashing, we

chose metaphase chromosome for taking photos. Somatic chromosome at mitosis metaphase of

Tylophora sui is 2n=22 (Figure 4). This basic number is identical with the report of Yamashiro et al.

(2002). They collected four species from Japan, all the basic number is n=11.

Ecology: This plant grows on open coral reef areas near seashore. In Taiwan many narrow

endemic species are confined to this area of Hengchun peninsula, including Cassia garambiensis

Hosok., Clematis terniflora DC. var. robusta (Carr.) Tamura, Crotalaria similes Hemsl.,

Chamaesyce garanbiensis (Hayata) Hara, Kalanchoe garambiensis Kudo, Derris microphylla (Mig.)

Jackson, Alpinia koshunensis Hay. and Premma hengchunensis Lu & Yang. This peninsula is

conceived as a phytogeographical island across which a demarcation line between the Boreal and

the Paleotropical floristic kingdom has been proposed (Takhtajan, 1986; Su, 1992).

IUCN Red List category: According to the IUCN Red List Categories and Criteria (IUCN, 2001)

this species is treated as vulnerable (VU) because its habitats are easily disturbed by human activity,

and is so far known only from southern Taiwan.

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Distribution: Known only from the type locality, Longpan, Hengchun (Town), Pintung (County),

Taiwan (Figure 6).

Notes: Tylophora sui closely resembles T. ovata (Lindl.) Hook. ex Steud., but it is distinct for

having creeping stems, villous indumentum on stems and glabrous adaxial surface of leaves. (vs.

twining stems, velutinous indumentum on stems; pilose on adaxial surface of leaves) (Figure 3).

The two species occupy different ecological niches: T. sui is found only at southern tip of Taiwan on

open coral reef areas near seashore ca.70 m elev. a. s. l. (Figure 6); whereas T. ovata (Lindl.) Hook.

ex Steud., a widespread species in Taiwan, is frequently found in semi shaded forest margins and

hilly site at low elevations throughout the island. In addition, T. sui is also closely similar to T.

rotundifolia Buchanan-Hamilton ex Wight, but it is distinguishable by having prostrate creeping

stems; glabrous adaxial surface of leaves; pedicle 0.5-1.3 cm; sepals without gland; (vs. twining

stems; adaxial surface of leaves with indumentum; pedicle 0.2-0.5 cm; sepals with 5 glands) (Table

1).

Table 1. Comparison of Tylophora sui, T. ovata and T. rotundifolia

T. sui (Figure 1, 2, 4) T. ovata (Figure 5) T. rotundifolia

Stems

Habit creeping twining twining

Indumentum villous velutinous velutinous

Leaves orbicular ovate ovate or obovate

Blade adaxial surface glabrous pubescent pubescent

Petiole length (cm) 0.5-1.3 0.5-3 0.2-0.5

Blade base cordate rounded rounded

Lateral veins 3-4 pairs 4-6 pairs 4-6 pairs

Peduncles (cm) 2-2.5 0.5-2 0.5-0.8

sparsely pubescent

to glabescent

dense pubescent dense pubescent

Rachis simple to 2 zigzag 2-4 zigzag simple zigzag

Pedicels glabrous

0.5-1.2 cm

sparsely pubescent

1-2 cm

pubescent

1-2.5 cm

Calyx sparsely hirsute

at apex

hirsute hirsute

Gland absent 5 or absent 5

Corolla glabrous on

both side

hirsute inside

glabrous outside

hirsute on both side

Chromosome number(2n) 22* 22* Non record

*= new recorded

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Acknowledgments: We thank Dr. Chern-Hsiung Ou(TCF) and Dr. Ching-I Peng(HAST) for valuable

comments, Dr. Qin-Er Yang (IBSC) for the Latin diagnosis, Dr. Yoshiko Kono(HAST) and Dr.

Shu-Chuan Hsiao for chromosome observation technical support, Ms. An-Ya Cheng for her line

drawing and Mr. Yu-Jung Hong for useful suggestions.

LITERATURE CITED

Forster, P. I. 1992. A taxonomic revision of Tylophora R. Br. (Asclepiadaceae: Marsdenieae) in Australia. Australian Systematic Botany. 5(1): 29 – 51.

Forster, P. I. 1994 A taxonomic revision of Tylophora (Asclepiadaceae: Marsdenieae) in Papuasia. Australian Systematic Botany. 7(5) 485 – 505.

Hatusima, S. 1963. New and noteworthy Asclepiadaceae plants from Formosa and the Ryûkyûs. Journal of Geobotany 12(1): 9-11.

Hayata, B. 1911 Materials for a flora of Formosa. Journal of the College of Science, Imperial University of Tokyo 30(1): 195-199.

Henry, A. 1896. A list of plants from Formosa, with some preliminary remarks on the geography, nature of the flora, and economic botany of the island. Transactions of the Asiatic Society of Japan 24:61.

IUCN. 2001. IUCN Red List Categories and Criteria, version 3.1. Prepared by the IUCN Species Survival Commission. IUCN, Gland, Switzerland, and Cambridge, United Kingdom.

Kawakami, T. 1910. A list of plants of Formosa. Bureau of Froductive Industry Government of Formosa, Taihoku (Taipei), Taiwan. p. 71.

Li, P. T., M. G. Gilbert and W. D. Steven 1995. Asclepiadaceae. In: Wu, Z. Y. and P. H. Raven (eds.). Flora of China 16: 189-270. Science Press, Beijing, China and MBG, St. Louis, Missouri, USA.

Lu, F. Y. and M. T. Kao 1978. Asclepiadaceae. In: Huang, T. C. et al. (eds.). Flora of Taiwan, 1st ed. 4: 243-246. Editorial Committee of the Flora of Taiwan, Department of Botany, National Taiwan University, Taipei, Taiwan.

Lu, F. Y., M. T. Kao, S. F. Huang and J. C. Wang 1998. Asclepiadaceae. In: Huang, T. C. et al. (eds.). Flora of Taiwan, 2nd ed. 4: 239-244. Editorial Committee, Department of Botany, National Taiwan University, Taipei.

Masamune, G. 1954. A list of vascular plants of Taiwan. Hokurikunoshoku Butzunokai Press, Kanazawa, Japan. p. 114.

Sasaki, S. 1928. List of plants of Formosa. The Natural History Society of Formosa, Taihoku (Taipei), Taiwan. p. 342.

Su, H. J. 1992. A geographical data organization system for the botanical inventory of Taiwan. Phytogeography and Botanical Inventory of Taiwan (Ching-I Peng, Ed.), Institute of Botany, Academia Sinica Monograph Series No. 12. pp. 23-36, Taipei.

Swarupanandan K. and D. H. Nicolson 1993 A new variety of Tylophora tetrapetala

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(Asclepiadaceae). Blumea. 38. 231-235. Takhtajan, A. 1986. Floristic Regions of the World. Transl. by Crovello, T. J. Univ.

California Press, Berkeley & Los Angeles. Tsiang, Y. and P. T. Li 1974. Praecursores Florae Asclepiadacearum Sinensium. Acta

Phytotaxonomica Sinica. 12(1):79-150. Yamashiro, T., M. Yokota, T. Denda, Y. Tateishi, J. Yokoyama and M. Maki 2002.

Chromosome numbers of Japanese Asclepiadaceae. Acta Phytotaxonomica et Geobotanica. 53(2): 143-152.

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A

B B’

C

I’

D D’ E

F F’

G

H I

J

K

5 cm A

0.3mm I I’

5 cm B

3 cm C

5 mm D5 mm E

5 mm F F’

5 mm G 5 cm J

1 cm K

Figure 1. Tylophora sui Y. H. Tseng & C. T. Chao A. Habit B. Leaf adaxial surface B’. Leaf

abaxial surface C. Inflorescence D.Corolla lobe inner surface D’ Corolla lobe outer

surface E. Calyx lobe F. Flower front side F’. Flower back side. G. Flower H.

Gynostegium I. Pollinarium outer surface I’. Pollinarium inner surface J. Fruit K. Seed.

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A B

C D E

F G

H I J

5 cm 3 cm 5 mm

5 cm 200 μm

50 μm 50 μm 10 μm

Figure 2. Tylophora sui Y. H. Tseng & C. T. Chao A-F Photos by digital camera A. Habitat B.

Habit C. Leaves D. Inflorescence E. Flower F. Fruits G.-J Photos by SEM G. Pollinarium H.

Retinaculum I. Pollinium J. Sculptural of pollinium surface.

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A B

Figure 3. Indumentum of genus Tylophora in Taiwan. A. T. ovata (Lindl.) Hook.

ex Steud. B. T. sui Y. H. Tseng & C. T. Chao

Figure 6. Distribution map of Tylophora sui Y. H. Tseng & C. T. Chao

2 μm

Figure 4. Somatic chromosome of Tylophora sui

Y. H. Tseng & C. T. Chao

2 μm

Figure 5. Somatic chromosome of Tylophora

ovata (Lindl.) Hook. ex Steud.