Spiradiclis pengshuiensis B. Pan & R. J. Wang, 2016

Pan, Bo, Ma, Hu-Sheng & Wang, Rui-Jiang, 2016, Spiradiclis pengshuiensis (Ophiorrhizeae, Rubioideae), a new species from Chongqing, China, PhytoKeys 63, pp. 41-45 : 42-44

Spiradiclis pengshuiensis B. Pan & R. J. Wang sp. nov. Figure 1

Diagnosis.

Spiradiclis pengshuiensis is similar to Spiradiclis pauciflora L. Wu & Q. R. Liu, from which it differs in having linear (vs. triangular) stipules, 4-6 (vs. 3-4) secondary veins each side of the leaf laminas, salverform (vs. funnelform) corolla with 9-15 mm (vs. 7-9 mm) long tubes (Table 1 ).

Type.

CHINA. Chongqing Municipality: Pengshui County, Hanxia Town , Baixiang Village , 29°8'N, 108°6'E, 360 m alt., 29 Nov 2014, Rui-Jiang Wang 2931, long-styled flower (holotype IBSC; isotypes IBSC) .

Description.

Perennial herbs, 4-9 cm tall, densely pubescent on plant surfaces; stems erect or prostrate at base and then ascending, terete, rooting at nodes; inter nodes 2-15 mm long. Stipules linear, 0.9-1.2 mm long. Petiole (3.5-)7-12(-23.5) mm long. Leaf blades opposite, ovate, (4-)7-15(-25) × (2.5-)5-10(-15) mm; base cuneate or late cuneate, asymmetry, decurrent; apex obtuse to rounded, papery, green adaxially and pale green abaxially; secondary veins 4-6 on each side; margin revolute slightly. Inflorescence terminal, cymose, 1-7(-12)-flowered but only 1-3 blooming simultaneously; peduncles 1-2.1 cm long; bracts and bracteoles linear, 1-2 mm long. Flowers distylous; pedicels 0-2 mm long; hypanthium obconical, 1-2 mm long; calyx lobes 5, lanceolate, 0.8-1.5 × ca. 0.4 mm. Corolla salverform, white adaxially, pinkish to white abaxially, pubescent both sides; tube 9-15 × 1.5-2 mm; lobes (4-)5, oval, 5-7.5 × 2.5-3.5 mm. Stamens 5; anthers linear-oblong, 1.5-2 mm long, dorsi-fixed. Stigma bilobed, lobes ovoid; ovary 2-celled, ovules many, axile. Long-styled flowers: stamens included; filaments adnate to the lower corolla tube, ca. 1.5 mm long; styles 9-12 mm long; stigma ca. 0.5 mm long, red to brown, extended to corolla throat, not exserted. Short-styled flowers: stamens extended to corolla throat, not exserted; filaments adnate to upper corolla tube, ca. 0.5 mm long; styles ca. 5 mm long; stigmas ca. 1.5 mm long, included. Capsules subglobose, 3-5 mm in diam., with persistent calyx lobes, dehiscent septicidally and loculicidally; valves 4, ovate, 3-5 mm long. Seeds 15-20 per capsule, ca. 0.5 mm long, brown, irregular pyramid to cuboid, foveolate on surface.

Phenology.

Flowers from November to next January; fruits from December to next February.

Distribution and habitat.

Spiradiclis pengshuiensis is known only from the type locality. Its habitat is on the cliffs nearby the A-Yi-He river but with very poor conditions.

Conservation status.

Only three small populations and less than 500 individuals of Spiradiclis pengshuiensis within 5 km2 were found in the A-Yi-He Scenic Area. The tourist activity is the primary factor in the decline of populations. In addition, the plants always grow on the cliffs with little soil and insufficient water, which limited the development and dispersal of the species. Therefore we assign a preliminary IUCN threat status of Vulnerable [VU, B2ab(ii, iii, iv)] to Spiradiclis pengshuiensis ( IUCN 2001).

Specimens examined.

CHINA. Chongqing Municipality: Pengshui County, Hanxia Town, Baixiang Village , 29°8'N, 108°6'E, 350 m alt., 29 Nov 2014, short-styled flowers, Rui-Jiang Wang 2932, 2937 (IBSC); same locality, 12 Jan 2016, fruiting, Rui-Jiang Wang 3095, 3099 (IBSC) .

Figures

Figure 1. Spiradiclis pengshuiensis sp. nov. A habitat B habit C linear stipules D visiting insects E bracts and hypanthium F-I longitudinal section of long- (F, H) and short-styled flowers (G, I), respectively, showing the induments, relative positions and morphology of the stigmas and anthers and the developing capsules in distylous flowers J infructescence K-L transverse and longitudinal section of young capsules, respectively M mature capsule N dehiscent capsules O seeds. Photos by Ruijiang Wang.