Primulina silaniae X.X.Bai & F.Wen, 2021

Zhang, Jin-Quan, Huang, Hong, Li, Mei-Jun, Huang, Mei, Li, Quan-Yuan, Zhou, Yu-Lu, Chen, Yi, Wen, Fang & Bai, Xin-Xiang, 2021, Primulina silaniae sp. nov. (Gesneriaceae) from the limestone area of Guizhou Province, China, PhytoKeys 185, pp. 123-130 : 123

Primulina silaniae X.X.Bai & F.Wen sp. nov.

Figures 1 , 2

Diagnosis.

The new species is similar to Primulina spiradiclioides , but can be easily distinguished from the latter by leaf margin entire with occasionally a few long hairs, glabrous on adaxial and abaxial surfaces (vs. margin serrate and not villous, lamina adaxial and abaxial surfaces densely whitish villous), no lateral veins on adaxial and abaxial surfaces (vs. inconspicuous on adaxial surfaces, distinctly raised on abaxial surface), pedicels 8-31 mm long (vs. ca. 5 mm), calyx inside glabrous (vs. sparsely pubescent), bluish-purple corolla lobes, with two short brownish-yellow stripes in the white throat (vs. corolla mouth white, forming a conspicuous pentagon), corolla tube slightly curved (vs. straight), ovary ca. 6mm long (vs. 2-2.5 mm), style 19-22 mm long (vs. ca. 2.5 mm), capsule, 8-9 mm long (vs. 10-15 mm).

Type.

CHINA, Guizhou Province: Wangmo County, Sanglang Town , 25°13'N, 106°26'E, altitude ca. 564 m, November 28, 2020, Xin-Xiang Bai et al., BXX20201128-01 (Holotype: GZAC!; Isotype: GZAC!; IBK!)

Description.

Herb perennial, lithophytic. Rhizomatous stem cylindrical, 0.9-1.2 cm long, ca. 0.5 cm in diameter. Leaves basal, fleshy and brittle, 8-18, crowded at the apex of stem; petiole occasionally villous, slightly concave on adaxial surface, 1-4 × 0.2-0.4 cm. Leaf blade oblong or oblanceolate, adaxially dark green, abaxially light green, 4-7 × 0.8-1.0 cm, glabrous on adaxial and abaxial surfaces, margin entire, occasionally a few long hairs, base tapering to petiole, apex acuminate to obtuse; midrib inconspicuous on adaxial surface, conspicuous on abaxial surface, no lateral veins. Cymes axillary, 1-4, 1-4-flowered; peduncle 3.2-12.5 cm long, ca. 1 mm in diameter, densely white pubescent; bracts 2, opposite, oblong, ca. 2.5 × 1 mm, adaxially pubescent, margin entire, apex acute; bracteoles ca. 2 × 0.5 mm, same color and indumentum as bracts; pedicels 8-31 mm long, ca. 0.8 mm in diameter, densely white pubescent; calyx 5-lobed, free from base, lobes equal, pale green, lanceolate to narrowly linear, ca. 9 × 1.5 mm, outside densely white pubescent, inside glabrous, margin entire, apex acute. Corolla infundibuliform, bluish-purple lobed, 3.3-3.6 cm long, two short brownish-yellow stripes with pubescent in white throat of the corolla; tube white, slender tubular, slightly curved, 2.8-3.1 cm long, base ca. 0.2 cm in diameter, mouth ca. 0.4 cm in diameter, tube outside sparsely pubescent in upper parts, lower parts and inside glabrous; limb distinctly 2-lipped, adaxial lip 2-lobed, lobes rounded, margin entire, ca. 6 × 5 mm; abaxial lip 3-lobed, lobes oblong, ca. 9 × 6 mm. Stamens 2, adnate ca. 16 mm above the base of the corolla tube; filaments ca. 6 mm long, terete; anthers coherent by entire adaxial surfaces, elliptic, ca. 2 × 1.5 mm, pale yellow, glabrous; staminodes 3, white, lateral ones ca. 2.1 mm long, adnate ca. 8 mm above the base of the corolla tube, terete, the middle one ca. 1.2 mm long, adnate to ca. 8 mm above the base of the corolla tube. Disk annular, yellow-green, margin entire, ca. 1 mm high. Pistils, ca. 2.6 cm long; style white, linear, 19-22 mm long, densely glandular-pubescent; ovary yellowish-green, ca. 6 mm long, glandular-pubescent. Stigma apex slightly 2-lobed; ca. 2 mm long, ca. 1 mm wide, Capsule narrowly cylindrical, longitudinal dehiscence, 8-9 mm long, ca. 3.5 mm in diameter; calyx and style persistent, white pubescent outside.

Etymology.

The epithet ‘silaniae’ is coined to honour Prof. Si-Lan Dai, the famous horticulturist at the Beijing Forestry University. She is also the former supervisor of one of the authors, Prof. Xin-Xiang Bai. Meanwhile, one of the given names of Prof. Si-Lan Dai, namely ‘Lan’, shares the same pronunciation in Chinese with the color blue. Thus, the scientific name also hints at the bluish to purplish-blue corolla of this new taxon.

Vernacular name.

Sī Lán Bào Chūn Jù Tái (Chinese pronunciation); 思兰报春苣苔 (Chinese name).

Phenology.

Flowering from November to February of the following year, fruiting from March to May.

Distribution and habitat.

The species has only been found in Wangmo County, the type locality. It grows on moist, shady limestone cliffs at altitudes of 550 to 570 meters.

Provisional IUCN conservation assessment.

At present, Primulina silaniae is only found in the type locality. There are three populations with ca. 600 matures individuals, all of which grow on moist and shady limestone cliffs. One of the populations has a small number of mature individuals and is located by the roadside, easily disturbed by human activities. It is therefore assessed as Vulnerable [VU D1] according to the IUCN Red List Categories and Criteria (Version 3.1) ( IUCN 2012, 2019).

Additional specimens examined.

Paratypes. CHINA Guizhou Province: Wangmo County, Sanglang Town , 25°13'N, 106°26'E, 416 m, a.s.l., 22 December 2020, Xin-Xiang Bai et al., BXX20201122-01 (GZAC!); The same locality, 11 April 2021, Xin-Xiang Bai et al., BXX20210411-01 (GZAC!); The same locality, 1 November 2020, Xin-Xiang Bai et al., BXX20201101-01 (GZAC!) .

Notes.

The leaf of Primulina silaniae is fleshy and brittle, glabrous on both sides, with an entire margint that occasionally has a few long hairs, base tapering to petiole, apex acuminate to obtuse; midrib inconspicuous on adaxial surface, conspicuous on abaxial surface, no lateral veins. These characteristics differ from those of other Primulina species and can be clearly distinguished from Primulina spiradiclioides in morphological characteristics (Table 1 ).

Figures

Figure 1. Primulina silaniae X. X. Bai & F. Wen, sp. nov. A habit B adaxial (left) and abaxial (right) surfaces of leaves C flowering cyme D young capsules E dissected calyx lobes F half opened corolla cover, showing stamens G stamens with cohering anthers. Drawn by Yi Chen from the holotype.

Figure 2. Primulina silaniae X. X. Bai & F. Wen, sp. nov. A, B habitat C front view of flower D, E oblique side view of flowers F plant G adaxial (left two) and abaxial (right two) surfaces of leaves H corolla I partial, enlarged leaf J partial, enlarged corolla tube K stamen L coherent anthers M dissected calyx lobes N lower distal part of corolla O pistil, pedicel and calyx with sepals removed P, Q dehisced and immature fruits. Photographs by Xin-Xiang Bai.