Spiradiclis guangdongensis H. S. Lo, Acta Botanica Yunnanica

Wang, Rui-Jiang, Wen, Hai-Zhen, Deng, Shu-Jun & Zhou, Lian-Xuan, 2015, Spiradiclis danxiashanensis (Rubiaceae), a new species from South China, Phytotaxa 206 (1), pp. 30-36 : 34-36

Spiradiclis guangdongensis H. S. Lo, Acta Botanica Yunnanica 9(3): 299. 1987, here emended. ( Fig. 2 : F–J.)

Type: — CHINA. Guangdong province: Huizhou City, Longmen County, Mt Nankunshan, Shangping Village, 6 April 1981, Nankunshan Expedition 71355 (holotype IBSC!).

Perennial herbs, mostly creeping or decumbent at terminal nodes; stems terete, slender, sparsely pubescent. Stipules entire or bipartite, lobes linear, 1–3.5 mm long. Petioles 2–6.5 mm long, sparsely pubescent; leaf blades orbicular, 0.5–1.2 × 0.5–1.1 cm, base rounded, apex obtuse, mucronulate or acute, papery, margin densely ciliate, sparsely hispidulous adaxially, glabrous or subglabrous abaxially, green adaxially, purplish abaxially or at least along veins; secondary veins 3–4 on each side; leaf epidermal cells irregularly polygonal on adaxial side, 73.8 × 45.6 μm, anticlinal walls sinuolate, periclinal walls with large and rugose irregular projections; abaxial cells irregularly polygonal, 94.3 × 47.1 μm, anticlinal walls sinuolate, periclinal walls with large and rugulose irregular projections; stomata paracytic ( Fig. 3D–F ). Flowers solitary, distylous, 5-merous; pedicels sparsely puberulent, 3–7.5 mm long; bracteoles linear, 1.5–3.0 mm long. Hypanthium obconical, 1–1.7 mm long, usually glabrous; lobes ovate to lanceolate, 1.3–2 × ca. 1 mm, with inconspicuous glands at each sinus. Corolla salverform, white, subglabrous outside; tube 0.8–1 cm long, 0.8–2 mm wide; lobes subovate, 4–7 mm × ca. 3 mm; stamens 5; anthers oblong-linear, 1.5–2.3 mm long; stigma bilobed. Long-styled flowers: corolla tube subglabrous inside but densely pubescent on throat; stamens included, filaments adnate to the lower corolla tube, ca. 1.5 mm long; styles exserted, 1.5–1.7 cm long, stigmas capitate. Short-styled flowers: corolla tube sparsely pubescent inside but densely on throat; stamens exserted, filaments adnate to the upper corolla tube, 5–10 mm long; styles included, 0.6–1 cm long, stigmas linear. Capsules ovoid, 1.1–1.7 mm long, with persistent calyx lobes. Seeds small, ca. 0.5 mm long, red, angular. Pollen grains released in monads; isopolar; rounded-triangular in polar view; spheroidal, 26.8 (25.5–29.0) × 27.8 (25.8–28.3) μm in long-styled flowers, with 0.96 P / E value; 3-colporate; tectum perforate ( Ma et al. 2005) or microreticulate ( Fig. 3 : M – O).

Distribution and habitat: —Known only from Mt Nankunshan of Guangdong province. Creeping over moist steeps or shaded rocks under the secondary forests, rare.

IUCN Conservation assessment: —The number of Spiradiclis guangdongensis locations is estimated less than guangdongensis (from R.-J. Wang 884), respectively.

five based on our field investigation.Although they all distributed in Mt Nankunshan National Forest Park, their habitats are at the roadside of tourist trails and have the plausible anthropogenic threat. Therefore the species is classified as VU under criterion D2, according to the guideline 8 of IUCN Standards and Petitions Subcommittee (2014).

Phenology:— Flowering in March–April and fruiting in April–July.

Additional specimens examined: — CHINA: Guangdong province, Huizhou City, Mt Nankunshan , 25 April 1932, W.- T. Tsang 20330 ( IBSC, paratype) ; Mt Nankunshan, Zhukengfeng , 18 May 1987, H.- S. Lo 1774 ( IBSC) ; Mt Nankunshan, Yixiantian , 113°50’ E, 23°36’ N, 720 m, 30 March 2009, R.- J. Wang 883 ( IBSC), 884 ( IBSC) ; ibid., 8 May 2011, R.- J. Wang & H.- Z. Wen 1573 ( IBSC), 1574 ( IBSC) ; ibid., 20 July 2011, R.- J. Wang, X. Guo , S.- J. Deng 1689 ( IBSC) ; ibid., 24 April 2013, R.- J. Wang & S.- J. Deng 2427 ( IBSC) ; ibid., 7 April 2014, R.- J. Wang 2672 ( IBSC), 2673 ( IBSC) .

Figures

FIGURE 2. Morphological characters of Spiradiclis danxiashanensis (A–E) and S. guangdongensis (F–J). A, F. Habit. B, G. Leaves. C, H. Long-styled flowers. D, I. Short-styled flowers. E, J. Young capsules. Photos by Rui-Jiang Wang

FIGURE 3. Micro-morphology of leaf and pollen of Spiradiclis danxiashanensis and S. guangdongensis. A–C. showing adaxial and abaxial epidermis and stomata of S. danxiashanensis (from R.-J. Wang & H.-Z. Wen 1549), respectively. D–F. showing those of S. guangdongensis (from R.-J. Wang, X. Guo, S.-J. Deng 1689), respectively. G–I. showing equatorial and polar views and microreticulate surface of pollen grains of long-styled flowers of S. danxiashanensis (from R.-J. Wang & H.-Z. Wen 1547), J–L. showing those of short-styled flowers of S. danxiashanensis (from R.-J. Wang & H.-Z. Wen 1546), and M–O. showing those of long-styled flowers of S.