Primulina pingnanensis Xin Hong, Z.L.Li & W.C.Chou., 2023

Li, Zheng-Long, Kuang, Yan-Yun, Xu, Qing-Qing, Chou, Wei-Chuen, Hong, Xin & Ding, Li, 2023, Primulina pingnanensis, a new species of Gesneriaceae from Guangxi, China, PhytoKeys 229, pp. 157-165 : 157

Primulina pingnanensis Xin Hong, Z.L.Li & W.C.Chou. sp.nov.

Fig. 1

Diagnosis.

Primulina pingnanensis morphologically resembles P. orthandra but is distinguished from the latter by bracts lanceolate (vs. ovate), corolla tube funnel-form and no constriction in the middle (vs. tube near tubular with constriction in the middle), outer corolla surface sparsely white puberulent (vs. glabrous), corolla lobes oblong (vs. broadly ovate), filaments strongly curved at the middle (vs. straight), anthers fused from the entire adaxial surface and sparsely barbate (vs. confluent at apex, glabrous), staminodes obvious, 1-1.3 cm long, sparsely pubescent (vs. ca. 1.5 mm long, glabrous). Detailed morphological comparisons with P. orthandra are provided in Table 1 and Fig. 2 .

Type.

China. Guangxi Zhuangzu Autonomous Region: Guigang City , Pingnan County, Shuangma Village , 23°37'N, 110°19'E, growing atop a cliff on a limestone hill, 28 March 2018, Chou Wei-Chuen, CWC180328-01 (holotype: IBK!; isotypes: AHU!, IBK!) .

Description.

Perennial herb. Rhizomatous stem subterete. Leaves basal, opposite, and congested at rhizome apex after years of growth; petiole 5-8 cm long, densely pubescent. Leaf blade dark green, thick herbaceous, elliptic to ovate-elliptic, 15-20 × 6-8 cm, apex acute to obtuse, base broadly cuneate, slightly oblique, margin sinuate, densely pubescent on both surfaces; 3-4 pairs of lateral veins on each side of the midrib; adaxially midrib main vein conspicuously sunken and lateral veins inconspicuously sunken, abaxially midrib main vein and lateral vein conspicuously raised. Cymes 1-7, axillary, 1-3-branched, 1-8(-16)-flowered; peduncles 18-25 cm long, densely brown puberulent and pubescent; bracts 2, opposite, lanceolate, ca. 7 × 2.5 mm, densely brown pubescent on both surfaces. Pedicels 2.5-4 cm long, densely brown puberulent, and pubescent. Calyx 5-lobed from the base, lobes narrowly lanceolate to triangle, apex acute, ca. 4 × 0.9 mm, outside pubescent, inside glabrous. Corolla zygomorphic, lilac, -4.5 cm long, outside sparsely white puberulent, inside glabrous; tube funnel-form, 2.0-3.0 cm long, 1.0-1.3 cm in diameter at the mouth, ca. 5 mm in diameter at the base; limb distinctly 2-lipped; dorsal lip 2-lobed to the middle, lobes ca. 1.0 cm long, apex suborbicular; ventral lip 3-lobed to the middle, lobes oblong, 1.0-1.5 cm long. Stamens 2, glabrous, adnate to the corolla tube for ca. 10 mm above the base; filaments 8-10 mm long, extending outwards at the base of the corolla, strongly curved at 90° degrees at the middle, sparsely white pubescent at base; anthers white, ca. 2 mm long, fused by the entire adaxial surface, sparsely barbate; Staminode 3, lateral ones obvious, linear, sparsely pubescent, 1-1.3 cm long, adnate to the corolla for 8 mm above the base; the middle one capitate, ca.1 mm long, adnate at the corolla base. Disc annular, slightly oblique, ca. 1.5 mm in height, margin repand. Pistil 2.8-3.2 cm long; ovary ca. 1.8 cm long, densely white pubescent; style ca. 1 cm long, densely puberulent; stigma trapeziform, ca. 2 mm long, apex slightly 2-lobed, lobes obtuse triangle, ca. 0.4 mm long. Capsule 4.5-6 cm long, sparsely brown puberulent, narrowly oblong-ovoid, dehiscing loculicidally into two valves.

Phenology.

Flowering from the second half of March to the first half of April, fruiting from June to July.

Etymology.

The specific epithet is derived from the type locality, Pingnan County. This county is the birthplace of Mr. Chou’s mother. Thus, Mr. Chou strongly suggested using " Primulina pingnanensis " as the scientific name.

Vernacular name.

Píng Nán Bào Chūn Jù Tái (Chinese pronunciation); 平南报春苣苔 (Chinese name).

Distribution and habitat.

Primulina pingnanensis is only known from the type locality, Shuangma Village, Pingnan County, Guigang City, Guangxi Zhuangzu Autonomous Region, growing on limestone cliffs at an elevation of ca. 50 m. The average temperature in the distribution area is 22.6 °C, while the average annual precipitation is 1050-2100 mm. The habitat is very close to the village with human activities.

Preliminary conservation assessment.

The terrain in the North and South of Pingnan County is mountainous, while the central area is flat. Very few limestone hills are in the plains, but some mountains are near Shuangma Village. After finding the new species, we conducted several detailed explorations of the area. The current survey results showed that this species has a small population at the top of a limestone mountain near Shuangma Village, with fewer than 200 individuals. According to the results of our field investigations in the type locality and adjacent regions, the EOO and AOO of Primulina Primulina pingnanensis are about 2 km2 and 0.1 km2, respectively. The severe drought in the second half of 2022 has seriously affected the population. According to the field survey, it is preliminarily estimated that the number of individuals in this population has decreased by 40% or more. More in-depth habitat surveys are warranted to determine if there are more populations nearby. For this current study, we temporarily assess the status of this species as Critically Endangered [CR B1+B2ab (iii, v)], according to the IUCN Red List Categories and Criteria (IUCN 2022).

Figures

Figure 1. Primulina pingnanensis Xin Hong, Z. L. Li & W. C. Chou A plants in natural habitat B cymes C opened corolla and dissected calyx lobes with pistil D leaves (up: adaxial surface, down: abaxial surface) E young fruit F bracts G stigmas H stamens.

Figure 2. Morphological comparisons between Primulina pingnanensis and P. orthandra A habit of P. pingnanensis B habit of P. orthandra C lateral view of mature flower of P. pingnanensis D lateral view of mature flower of P. orthandra E staminodes of P. pingnanensis F staminodes of P. orthandra G filaments of P. pingnanensis H filaments of P. orthandra I bracts of P. pingnanensis J bracts of P. orthandra.