Primulina xuansonensis W.H.Chen & Y.M.Shui, 2020

Chen, Wen-Hong, Guo, Shi-Wei, Nguyen, Hieu Quang, Chen, Li & Shui, Yu-Min, 2020, Two new taxa of Gesneriaceae in the karst regions in North Vietnam, PhytoKeys 157, pp. 217-226 : 217

Primulina xuansonensis W.H.Chen & Y.M.Shui sp. nov. Figure 3

Type.

Vientam. Phu Tho Province: Xuan Son County, Xuan Son National Park, 21°07'01"N, 104°57'29"E, 438 m a.s.l., without flowers and fruits, 8 April 2016, introduced at Kunming Botanical Garden, in flower from October to December 2017, Y. M. Shui, W.H. Chen, C. Liu, H.Q. Nguyen, H.T. Nguyen, N.Q. Chuong B2017-1341 (holotype, KUN!; isotype, CPC!).

Diagnosis.

The new species is similar to Primulina lungzhouensis (W.T. Wang) Mich. Möller & A.Weber in having prominent bracts, with a corolla, the outside of which is white. However, it differs in its bracts 1.6-2.5 × 1.3-1.5 cm (vs. bracts 2.5-3.8 × 2.2-2.8), corolla 3-3.5 cm long (vs. corolla 4.5-5 cm long), corolla tube slightly curved near the base (vs. not curved), inflated on the adaxial surface near the corolla lobes (vs. not inflated) and corolla abaxial lip lobes rounded (vs. triangular).

Herbs perennial. Stem absent. Leaves basal; petiole 2-5 cm long, strigose; blade carnose and papyraceous when dry, ovate to rounded, 11-18 × 8.5-11 cm, base cuneate, apex round, margin crenate from the base, adaxially sparsely strigose, abaxially sparsely strigose; venation penninerved, lateral veins 5-7 on each side of the midrib. Cymes umbel-like, axillary, ca. 9-flowered; peduncle 6.5-8.5 cm long, densely strigose; bracts 2, triangular-ovate, 1.6-2.5 × 1.3-1.5 cm, both sides densely strigose, margin with ca. 2-minute dentes near apex; pedicel 1-1.2 cm long, glandular-pubescent; bracteoles 2, narrowly ovate, ca. 1.2 × 0.4 cm, both sides densely strigose. Calyx 5-parted to the base, segments lanceolate, 0.8-1 × ca. 0.3 cm; apex acute, margin entire, outside glandular-pubescent, inside strigose. Corolla funnelform, zygomorphic, 3-3.5 cm long, ca. 0.8 cm wide at the throat, outside white, densely glandular-pubescent, inside white with two yellow stripes along the abaxial lip, glabrous; tube 2-2.3 cm, slightly curved near the base; limb 2-lipped; adaxial lip 2-lobed, lobes broadly ovate, ca. 0.5 × 0.8 cm; abaxial lip ca. 1.2 × 1.7 cm, 3-lobed to the middle, lobes rounded, middle lobe ca. 0.8 × 0.7 cm, lateral lobes ca. 0.6 × 0.7 cm. Stamens 2, adnate to the abaxial side of corolla tube ca. 1.4 cm above base; anthers glabrous; filaments glabrous, ca. 0.5 cm long; staminodes 3, ca. 1 mm long, glabrous, lateral two adnate to ca. 1 cm above the corolla base, central staminode adnate to ca. 0.6 cm above the corolla base. Disc ring-like, 1-2 mm high. Pistil glandular-pubescent, ca. 1.6 cm long; ovary linear, ca. 1 cm long; style linear, ca. 0.6 cm long; stigma cuneate, 2-lobed. Capsule unknown.

Phenology.

Flowering from October to December, fruiting from December to January from cultivated plants.

Etymology.

The name refers to the type locality.

Distribution and habitat.

The new species only grows in the limestone forests’ rock crevices and distributes in the type locality, Xuan Son National Park of Pho Tho Province, North Vietnam.

Provisional conservation status.

We observed it in the field with very few individuals (about ten individuals). Due to the similarity of plants without flowers in the genus Primulina , we did not pay attention to the species in the field, so the number of mature individuals remains unknown. Provisionally, it is best to consider it as Data Deficient (DD) ( IUCN 2012; IUCN Standards and Petitions Subcommittee 2017).

Note.

Within the genus Primulina , there is a morphological species complex with prominent shell-like bracts, such as P. beiliuensis B. Pan & S. X.Huang, P. eburnea Hance, P. lunglinensis (W.T. Wang) Mich. Möller & A.Weber, P. lungzhouensis , P. maguanensis (Z.Yu Li, H.Jiang & H.Xu) Mich. Möller & A.Weber, P. minutimaculata (D. Fang & W. T. Wang) Yin Z.Wang, P. obtusidentata (W.T. Wang) Mich. Möller & A.Weber and P. tribracteata (W.T. Wang) Mich. Möller & A.Weber (e.g. Wang et al. 1998; Wei et al. 2010; Pan et al. 2013; Shui et al. 2017; Wen et al. 2019). Within the above complex, the new species is different from all the others in its white throat outside the corolla, except for P. lungzhouensis . Furthermore, the new species is different from P. lungzhouensis in its bracts 1.6-2.5 × 1.3-1.5 cm, corolla 3-3.5 cm long, corolla tube slightly curved near the base, inflated on the adaxial surface near the corolla lobes and corolla abaxial lip lobes rounded. P. lungzhouensis , however, has bracts 2.5-3.8 × 2.2-2.8 cm, corolla 4.5-5 cm long, corolla tube not curved, not inflated on the adaxial surface near the corolla lobes and corolla abaxial lip lobes triangular. In a word, the new species is unique in its narrow and curved corolla tube amongst the above complex with prominent bracts (Table 2 ).

Figures

Figure 3. Primulina xuansonensis W. H. Chen & Y. M. Shui, sp. nov. (A-H) and its similar species P. lungzhouensis (W. T. Wang) Mich. Moeller & A. Weber (I-J) A habit B view of adaxial leaf C inflorescence D bracts E face view of flower F lateral view of flower G birds-eye view of the opened corolla, arrow showing the staminodes (sta.) H pistil and calyx, arrow showing the disc ring I habitat of P. lungzhouensis J face view of flower and bracts.