Primulina papillosa Z.B. Xin, W.C. Chou & F. Wen, 2021

Xin, Zi-Bing, Chou, Wei-Chuen, Maciejewski, Stephen, Fu, Long-Fei & Wen, Fang, 2021, Primulina papillosa (Gesneriaceae), a new species from limestone areas of Guangxi, China, PhytoKeys 177, pp. 55-61 : 55

Primulina papillosa Z.B. Xin, W.C. Chou & F. Wen sp. nov. Figs 1 , 2E-F

Diagnosis.

The new species resembles Primulina linearifolia (Fig. 2A, B ) and P. pseudolinearifolia (Fig. 2C, D ), but can be easily distinguished from the latter two by both surfaces of its leaf blades being densely papillose-hispid. It differs from P. linearifolia by its 1-2-flowered per cyme (vs. 4-7-flowered); pedicel 20-35 mm long (vs. 5-12 mm); calyx lobes 7.5-9 mm long (vs. 3.2-4 mm); disc ca. 1.2 mm high, margin entire (vs. ca. 0.5 mm, margin repand); capsule 5-6.5 cm long (vs. 2.2-3.6 cm). It also differs from P. pseudolinearifolia by its 1-2-flowered per cyme (vs. 4-12-flowered); pedicel 20-35 mm long (vs. 7-15 mm); central staminodes ca. 0.5 mm long (vs. ca. 3 mm); disc ca. 1.2 mm high, margin entire (vs. ca. 2.5 mm, margin repand).

Type.

China. Guangxi: cultivated material in the Gesneriad Conservation Center of China and National Gesneriaceae Germplasm Resources Bank , harvested on 24 October 2020, wild-collected, from Dingdang Town , Longan County, Nanning City , 23°07'N, 107°57'E, 9 April 2020, W.C. Chou 20200409-01 (Holotype, IBK!; Isotypes, IBK!) .

Description.

Herbs perennial. Rhizome thickened, woody, subterete, 10-15 cm long, 1.5-2 cm in diameter, internodes inconspicuous, commonly branched at the apex of the rhizome or not branched. Leaves 15-25, congested at the apex of the rhizome, subsessile; leaf blade fleshy, linear-lanceolate, 5-15 × 0.9-1.8 cm, densely papillose-hispid on both surfaces, apex obtuse to round, base attenuate, margin entire, lateral veins 2-4 on each side of the mid-rib, conspicuous on the abaxial surface, inconspicuous on the adaxial surface. Cymes 2-5, axillary, 1-2-flowered; peduncle 4-8 cm long, ca. 2 mm in diameter, glandular-pubescent and sparsely pilose; bracts 2, opposite, linear-lanceolate, 6-8 × 1-1.5 mm, apex acute, margin entire, pubescent on both surfaces, pedicel 2-3.5 cm long, ca. 2 mm in diameter, glandular-pubescent. Calyx 5-parted from the base, segments equal, lanceolate, 7.5-9 × ca. 2 mm, abaxially glandular-pubescent, adaxially sparsely glandular-pubescent to glabrous, apex acute, margin entire. Corolla purple, throat with two yellow stripes inside, 3.5-4.5 cm long, outside puberulent with both glandular and eglandular hairs, inside glabrous, tube 2.5-3 cm long, orifice 0.8-1.5 cm in diameter; limb distinctly 2-lipped, adaxial lip 2-parted to the middle, with a yellow patch between the two adaxial lobes, lobes ovate, 6-7 × 8-9 mm, abaxial lip 3-parted to near the base, lobes ovate, 8-9 × 9-10 mm. Stamens 2, adnate ca. 1.2 cm above the corolla base; filaments 1.3-1.5 cm long, geniculate near the middle, sparsely pubescent; anthers reniform, 3.5-4 mm long, bearded; staminodes 3, lateral ones linear, glabrous, ca. 9 mm long, apex capitate, sparsely pubescent, adnate to ca. 1 cm above the corolla tube base, the central one ca. 0.5 mm long, apex capitate, adnate to 3.5 mm above the corolla tube base. Disc annular, ca. 1.2 mm high, margin entire, glabrous. Pistil 2.5-3 cm long, ovary 1.4-1.6 cm long, ca. 2 mm in diameter, densely glandular-pubescent and eglandular-pubescent; style 0.9-1.2 cm long, 1.5 mm in diameter, glandular-pubescent and eglandular-pubescent; stigma obtrapeziform, ca. 2 mm long, apex shallowly 2-lobed. Capsule linear, 5-6.5 cm long, 2-3 mm in diameter, puberulent with both glandular and eglandular hairs.

Phenology.

Flowering from September to November, fruiting from October to December.

Etymology.

The specific epithet ' Primulina papillosa ' is derived from the leaf blade densely papillose-hispid on both surfaces.

Vernacular name.

The Chinese name ‘刺疣报春苣苔’ ( Cì Yóu Bào Chūn Jù Tái) is newly coined for this species because of its special leaf blades surface full of densely papillose-hispid hairs.

Distribution and habitat.

Primulina papillosa is only known from the type locality, Dingdang Town, Longan County, Nanning City, Guangxi, China. It only grows in crevices of the cliff near the top of limestone hills in a subtropical evergreen seasonal rain forest.

Conservation status.

Primulina papillosa is only found from the type population with less than 200 individuals. The EOO and AOO of the new species are about 1.05 km2 and 0.01 km2, respectively. The beautiful flowers, thickened rhizomatous woody stem and leaves with dense papillose-hispid hairs, have led to its over-harvesting by local people who have sold it as an ornamental plant. Furthermore, the natural habitat is mostly disturbed due to local farmers imposing intense pressure on the remaining patches of primary forest. Thus, following the IUCN Red List Categories and Criteria ( IUCN 2019), it is temporarily assessed as Critically Endangered [CR B1+B2ab (iii, v)].

Figures

Figure 1. Primulina papillosa A, B habitat C habit D front view of the corolla E lateral view of the corolla F top view of the corolla G adaxial and abaxial surface of leaf blades H papillose-hispid hairs on leaf blade surface I stamens J pistil, calyx and opened corolla with stamens and staminodes. (A, B photos by W. C. Chou, C-J photos by F. Wen; arranged by Z. B. Xin).

Figure 2. Comparison of three species of Primulina A, B P. linearifolia C, D P. pseudolinearifolia E, F P. papillosa. (photos by F. Wen; arranged by Z. B. Xin).