Smilax hirtellicaulis C.Y.Wu & C.Chen ex P.Li., 2016

Jin, Xin-Jie, Chen, Yao, Lee, Joongku, Qi, Zhe-Chen, Liu, Lu-Xian, Li, Pan & Fu, Cheng-Xin, 2016, A new species of Smilax (Smilacaceae) from Yunnan, China, Phytotaxa 275 (2), pp. 159-167 : 163-166

Smilax hirtellicaulis C.Y.Wu & C.Chen ex P.Li. sp. nov. ( Figs. 2 , 3 )

The new species resembles Smilax glabra Roxburgh in possessing coriaceous leaves, leaf blade elliptic or ovate and bronze-colored tendrils, but differs in having a rhizome like a string of beads (vs. tuber-like), square and hirtellous stems (vs. terete and smooth), male flowers with 6 staminodes (vs. 3), and female flowers with separate tepals (vs. basally connate).

Type:— CHINA. Yunnan Province: Hekou County, south slope of Mt. Beishan, 134 m, 103°55’44.238”E, 22°32’24.036”N, 12 May 2016, Fl. (♂), Hanyang Lin & Xiaoming Zheng Hk04 (holotype HZU60127244!).

Perennial woody vine, climbing with tendrils. Stems quadrangular, prickless, smooth when young and hirtellous at maturity. Petioles 1.1–3.2 cm long, narrowly winged for 1/10 to 3/5 of their length, pubescent at maturity; abscission zone subapical; stipular tendrils well developed, born on the apical portion of petioles, green when young, then becoming bronze–colored at maturity. Leaf blade elliptic or ovate with acuminate apex, base broadly cuneate to shallow cordate, 5.3–19.2 cm long, 2.4–12.3 cm wide, coriaceous, green and glossy above and beneath, 3 primary veins and 2 marginal vein; Inflorescence of 1 umbel, occasionally 2 umbels, born in leaf axil, basally prophyllate; peduncle 1.2–1.9 cm long, straight, slightly compressed and pubescent; umbel 8–28 flowered, hemispherical, base thickened, globose, 2–3 mm in diameter, bracteoles many. Pistillate flowers born on pedicels 6.3–7.5mm long, yellow–greenish; tepals 6, elliptic to ovate, 3.7–3.8 mm long, 2.0– 2.1mm wide, thickened, adaxially verruculose; staminodes 6; ovary superior. Staminate flowers born on pedicels 8.9–13 mm long, yellow–greenish; tepals 6, 4.2–4.3mm long, thickened, adaxially verruculose, outer ones 2.3–2.4mm wide, inner ones slightly narrower, outer ones and inner ones connate for ca. 1/3 their length and forming a disc, giving the appearance of one whorl in 6, rather than 2 whorls in 3; stamens 6, anther wide oblong, filaments short and ampliate, wider than anther, connate. Berries 4–4.2 mm in diameter (based on KUN0351106!, KUN0351107!, KUN0351382!; fresh fruits not seen), Fl. May. Fr. June.

Additional specimens seen (paratypes):— CHINA. Yunnan Province: Hekou County, south slope of Mt.

Beishan, 134 m, 103°55’44.238”E, 22°32’24.036”N, Fl. (♀), 12 May 2016, Hanyang Lin & Xiaoming Zheng Hk01

(HZU60127241!); ibidem, Fl. (♀), Hanyang Lin & Xiaoming Zheng Hk02 (HZU60127242!, HZU60127243!); ibidem, Fl. (♂), Hanyang Lin & Xiaoming Zheng Hk03 (HZU60127241!, HZU60127245!); Hekou County, south slope of Mt. Beishan , 134 m, 103°55’44.238”E, 22°32’24.036”N, 21 March 2016, Xinjie Jin JXJ2016032058 ,

Xinjie Jin JXJ2016032059, Xinjie Jin JXJ2016032060, Xinjie Jin JXJ2016032061, Xinjie Jin JXJ2016032062,

Xinjie Jin JXJ2016032063, (HZU60127239!, HZU60127240!, HZU60127249!, HZU60127248!, HZU60127247!,

HZU60127246!); Hekou County, Mt. Beishan, 180 m, 30 November 1993, Chengxin Fu 93031 (HZU60088564!,

HZU60088562!); Hekou County, Wayao, 120m, Fr., 29 June 1953, Xinwei Liu 130 (KUN0351106!, KUN0351107!,

KUN0351382!); Hekou County, Mahuangbao, 140 m, Fl., 7 May 1953, Wenguan Fan 81 (KUN0352043!); Hekou

County, Bazihe, 220 m, 25 April 1953, Kehua Cai 578 (KUN0352045!).

Etymology:—The Latin word ‘ hirtelli ’ means hirtellous and ‘ caulis ’ means stem. We validly publish here the nome nudum Smilax hirtellicaulis to honor Zhengyi Wu and Jie Chen, Kunming Institute of Botany (KUN), for their great contribution to the field of Botany.

Distribution and habitat:—This new species is only known from Hekou County, southern Yunnan Province, China. Till now, it has been recorded at four localities of Hekou County ( Fig. 4 ). The type locality is less than 1 km away from the border of Vietnam, where it grows on hill slope from 120–220 m near the edge of artificial cedarwood or rubber forests ( Fig. 3 ). Thus, this species is likely to also occur in Vietnam.

Conservation Status:—At the type locality (Beishan, a small hill in Hekou County), Smilax hirtellicaulis was found in heavily altered vegetation and survived in repeated anthropogenic activities, such as tree plantation and road construction. They must have persisted there for at least twenty years, and the population is not declining at all based on our observations. The population is still very large by now, with hundreds or even thousands of individuals, and they spread all over the hill, even around construction sites. Based on the herbarium records, three other localities in Hekou County (Wayao, Mahuangbao and Bazihe) also have this new species. Considering the insufficient botanical investigations in Hekou and nearby regions, we believe that it has a much wider distribution than what we known now. Thus we suspect that Smilax hirtellicaulis could be categorized as Least Concern according to IUCN criteria ( IUCN 2014).

Taxonomic and evolutionary relationships:—For all known Smilacaceae species, the separation/connation patterns of tepals in male and female flowers are identical, e.g., separate in both genders, or basally connate in both, or completely connate in both. However, our new species added a fourth pattern that the tepals are basally connate in male flowers but separate in female flowers. It is the first of its kind, and also helps us make better sense of the diversity and evolution of Smilacaceae . The discovery of this new species is very important because of the morphological transition between the Smilax sect. Heterosmilax with united tepals and most of other Smilax taxa with separate tepals. The closest phylogenetic relationship and resembled flower morphology between Smilax hirtellicaulis and sect. Heterosmilax may represent an evolutionary transition from separate to united tepals in Smilax . It thus provides us an ideal model for studying the evolution and development of such an innovative floral trait in the future.

Figures

FIGURE 2. Illustration of Smilax hirtellicaulis C.Y.Wu & C.Chen ex P.Li. (A). Fertile branch with pistillate inflorescences and fruits. (B). Staminate inflorescence. (C). Staminate flower in front view. (D). Staminate flower in rear view, showing basally connate tepals. (E). Six stamens, showing connate filaments. (F). Anther in front view. (G). Anther in side view. (H). Pistillate flower in front view. (I). Pistillate flower in side view. (J). Ovary in side view. (K). Transversal section of ovary. (L). Six amphitropous ovules bearing at the axile placentation. (M). Outer tepal of pistillate flower. (N). Inner tepal of pistillate flower. (O). Rhizome.

FIGURE 3. Smilax hirtellicaulis C.Y.Wu & C.Chen ex P.Li. (A). Plant habitat: in artificial cedarwood or rubber forests. (B). Plant habit. (C). Stem section with leaf in adaxial view and staminate inflorescence. (D). Stem section with leaf in abaxial view and staminate inflorescence. (E). Rhizome. (F). Staminate inflorescence. (G). Pistillate inflorescence. (H). Peduncle, stem and petiole. (I). Staminate flower in front view. (J). Staminate flower in rear view. (K). Pistillate flower in side view. (L). Outer tepal (bottom row) and inner tepal (top row) from a pistillate flower.

FIGURE 4. Distribution records of Smilax hirtellicaulis C.Y.Wu & C.Chen ex P.Li, sp. nov. (red stars) from Hekou County, Yunnan Province, China.