Spiradiclis karstana L.Wu, X.Li & Q.R.Liu, 2019

Wu, Lei, Li, Xiong, Liu, Wen-Jian & Liu, Quan-Ru, 2019, Spiradiclis karstana (Rubiaceae), a new species from Yunnan, China, PhytoKeys 117, pp. 1-8 : 2-5

Spiradiclis karstana L.Wu, X.Li & Q.R.Liu sp. nov. Figures 1 , 2

Diagnosis.

Similar to S. jingxiensis , but differing from this species by the ovate-triangular stipules less than 1 mm long (vs. stipules linear, 1.5-3.0 mm long), the elliptic to oblong leaf blades (vs. ovate to broadly ovate), the 5-12 pairs of secondary veins (vs. 4-5 pairs) and the inflorescences with 5-9 flowers (vs. inflorescences with 1-2 flowers).

Type.

CHINA. Yunnan Province: Malipo County, Mali town, Luoshuidong village, 23°03'N, 104°43'E, 900 m alt., 11 Apr. 2018, Ming-Feng Long & Lei Wu MLP0002 (holotype: CFSI; isotype: CFSI).

Perennial herbs, up to 8 cm in height, prostrate or decumbent, usually rooting at nodes; stems terete, basal part usually woody, densely puberulent (trichomes white). Petiole 2-7 mm long; leaf blade elliptic to oblong, 0.8-4.5 × 0.5-1.6 cm, drying papery, adaxially green, abaxially yellowish-green, adaxially puberulent to subglabrous, abaxially puberulent, densely pubescent along principal veins on lower surface; base cuneate and somewhat decurrent, apex obtuse to acute; secondary veins 5-12 pairs, both midrib and secondary veins adaxially impressed, abaxially prominent; stipules ovate-triangular or sometimes 2-lobed, 0.2-0.8 mm long, densely puberulent outside, usually deciduous. Inflorescences terminal, cymose, 5-9-flowered, puberulent; peduncles short, 1.5-2.4 mm long, puberulent; bracts subulate, 0.5-1.5 mm long, puberulent. Flowers distylous; pedicels 1.0-2.5 mm long, puberulent. Calyx puberulent to subglabrous outside; hypanthium obconic, 1.2-1.7 mm long; calyx lobes equal, lanceolate to narrowly triangular, 2-2.5 mm long, acute at apex. Corolla 5-merous, slenderly salverform, purple-reddish, with a deep purple-reddish ring around the throat, glabrous outside; tube 15-25 mm long; lobes broadly ovate, 3.5-6.0 × 3.0-5.0 mm, apically rostrate-incurved; stamens completely included in the corolla tube at anthesis in both flower morphs; ovary 2-celled. Long-styled flowers: inside with a ring of hairs near the stamens; stamens inserted near the base and stigma positioned a little below the throat of the corolla tube; anthers linear, ca. 2.0-2.4 mm long; stigma 2-lobed, lobes elliptic, ca. 1.2 mm long. Short-styled flowers: inside with sparse pubescence near the base of the corolla tube; stamens inserted above the middle and stigma positioned near the base of the corolla tube, anthers linear, ca. 2.5 mm; stigma 2-lobed, lobes ovate-lanceolate, ca. 1.5 mm long. Capsule obovoid, 2.5-3.5 mm long, subglabrous, opened at the top when mature. Seeds ca. 12 per capsule.

Phenology.

Flowers and fruits were observed in April. We think flowering and fruiting may extend till May, because many flowers in April were still in bud.

Distribution and habitat.

Spiradiclis karstana is known only from the crevices of forested cliffs at altitudes ranging from 800 to 1600 m in the karst area of SE Yunnan. This part of Yunnan is covered by evergreen rain forests that are highly similar to those in Indo-Malaysia ( Zhu 2013) and are dominated by species from Magnoliaceae , Lauraceae , Dipterocarpaceae and Annonaceae .

Etymology.

The specific epithet refers to the habitat of the new species.

Specimens examined (paratypes).

CHINA. Yunnan Province. Malipo County, Mali town, Luoshuidong village, 25 Apr 2017, Ming-Feng Long MLP 0001 (CFSI); Mengzhi city, Shuitian town, on a karst cliff, alt. 1650 m, 29 Apr 2017, Meng-Qi Han et al. HMQ0001 (IBK).

Conservation status.

So far, only two populations with about 300 individuals each have been found, notably near the towns of Mali and of Shuitian. The area of occupancy is estimated to be less than 4 km2. Despite the fact that only two populations with relatively few individuals are known, the status of Spiradiclis karstana is not pessimistic. It may count on the strong adaptability of the species to the severe habitat where interference from humans is usually weak and where it is very hard for people to reach and the efficient government policy to protect the local vegetation ( Lai et al. 2000, Sui and Chen 2006, Zhu et al. 2007). Considering all of the above, this species is therefore assigned a status of “Vulnerable” [VU B2ab(ii, iii, iv)] according to the IUCN criteria (2016).

Figures

Figure 1. Spiradiclis karstana sp. nov. A habit B stipule C inflorescence, side view D long-styled flower E short-styled flower F calyx, frontal view, showing disc G remnant of dehiscent capsule, frontal view. Drawn by Xin-Yi Zeng.

Figure 2. Spiradiclis karstana sp. nov. A habitat (The arrows show the places of growth) B habit C variation range of leaves D stipule E inflorescence, side view F long-styled flower, frontal view G disc and calyx H remnant of dehiscent capsule, frontal view I long-styled flower J short-styled flower. Spiradiclis jingxiensis K habit L stipule M variation range of leaves. Photos by Lei Wu, Ming-Feng Long and Xin-Xin Zhu.