Primula wolongensis W.B.Ju, Bo Xu & X.F.Gao, 2023

Li, Xiong, Cheng, Yue-Hong, Lin, Hong-Qiang, Chen, Cheng, Gao, Xin-Fen, Deng, Heng-Ning, Yu, Feng, Anđelka, Plenkovic-Moraj, Ju, Wen-Bin & Xu, Bo, 2023, Primula wolongensis (Primulaceae), a new species of the primrose from Sichuan, China, PhytoKeys 218, pp. 47-57 : 47

Primula wolongensis W.B.Ju, Bo Xu & X.F.Gao sp. nov.

Diagnosis.

Amongst the Chinese members of subsect. Primula Petiolares Chartacea , the new species is easily recognized by the following combination of characters: leaf blade margin dentate, leaf veins which are not raised, scape which is shorter or equal with pedicel, corolla yellow and location of stamens of the corolla tube at thrum flower. The new species is morphologically similar to P. arunachalensis Basak & Maiti and P. fenghwaiana C.M.Hu & G.Hao, but can be easily distinguished from P. arunachalensis by its shorter rootstocks, petioles 3-5 × as long as leaf blade (versus 1-2 × as long as leaf blade), reticulation of veins obscure on both surfaces (versus veins slightly impressed adaxially and conspicuous abaxially), corolla lobes apex emarginate (versus corolla lobes margin denticulate to lacerate), heterostylous (versus homostylous). Compared with P. fenghwaiana , the difference of the new species is the petioles 3-5 × as long as the leaf blade (versus ca.2/3 the length of the leaf blade), leaf blade base cordate (versus base broadly cuneate to almost rounded), leaf blade margin irregular dentate (versus margin remotely denticulate), scapes and pedicels sparsely short-stalked glandular (versus densely covered with minute glandular hairs), corollas yellow (versus pink to white), the position of stamens at thrum flower tube on the middle (versus on the apex).

Type.

China. Sichuan: Wenchuan City, Wolong National Nature Reserve , growing in moist rock crevices covered with moss. 31°04'N, 103°11'E, elevation ca. 3400 m, 18 May 2021 (fl./fr.), Y.H. Cheng & H.Q. Lin XuBo 2771 (holotype CDBI!; isotypes KUN!, PE!). (Figs 2 - 4 )

Description.

A perennial plant, efarinose, having reddish-brown basal bud scales, second-year buds at the base and free from bud scales at flowering time, rootstock extremely short. Roots numerous, fibrous. Leaves forming a loose rosette; young leaf blade often fold, widely ovate to suborbicular at maturity, 1.0-3.5 × 1-2.5 cm, broadly obtuse to rounded at apex, with a cordate base, margin irregular dentate, glabrous on both surfaces, glaucous below, firm papery when dry, lateral veins 3-5 pairs, slightly impressed adaxially, reticulation of veins obscure on both surfaces; petioles 3.0-8.5 cm long, sparsely short-stalked glandular, reddish brown. Scape 1, sparsely short-stalked glandular, 1.8-4.5 cm tall, non-elongating at fruiting time; umbel with 1-3 flowers; bracts linear to linear-lanceolate, 0.7-1.5 cm long; pedicels 1.5-4.5 cm long, densely short-stalked glandular, not extended in fruit. Flowers heterostylous. Calyx green, campanulate, 6-11 mm long, slightly enlarged, poculiform in fruit, short-stalked glandular, parted slightly below middle to 2/3; lobes ovate-lanceolate, margin entire, apex acute. Corolla yellow with short-stalked glandular, annulate; limb 16-25 mm across, funnelform; lobes spreading, 7-12 × 5-10 mm, broadly obovate, emarginate. Thrum flower: corolla tubes 8-12 mm in length, 3-4 mm in diameter, slightly longer than calyx, widely ampliated above insertion of stamens; stamens inserted slightly above the middle of corolla tube; style ca. 4 mm. Pin flower: corolla tubes 7-10 mm in length, ca. 3 mm in diameter, nearly equal to calyx, widely ampliated above insertion of stamens; stamens in the middle of corolla tube, style ca. 2/3 as long as tube. Capsule globose, included in calyx, disintegrating at maturity.

Phenology.

Flowering May-June, fruiting May-August.

Etymology.

The specific epithet refers to the type locality, Wolong National Nature Reserve.

Vernacular name.

A Chinese name, wo long bao chun (卧龙报春), is suggested here.

Distribution and habitat.

The species has so far only been found at its type locality in Wolong Town, Wenchuan county, Sichuan Province. It grows in the cracks of steep wet cliffs covered with moss above the tree-line.

Conservation status.

Data Deficient (DD). Currently, only one population with more than 100 individuals has been found in the type locality. According to the guidelines for using the IUCN Red List categories and criteria ( IUCN Standards and Petitions Subcommittee 2022), the conservation status of the new species is 'Data Deficient (DD)'. Further explorations in the adjacent mountainous tracts are necessary for an adequate assessment.

Discussion.

Following Hu’s (1990) taxonomic treatment of this genus, this new species belongs to Primula section Petiolares on account of globose capsule included within the calyx-tube that does not open by valves but apically crumbling at membrane apex at maturity (Figs 2 - 4 ).

Further morphological analysis shows that the new species is allied with subsect. Primula Petiolares Chartacea by having glabrous and efarinose plants, at flowering time devoid of basal bud-scales, more or less rounded blades and slender petioles.

Including the newly described here, there are nine species reported so far for this subsection ( Smith and Fletcher 1944; Hu 1990; Basak and Maiti 2000; Rankin 2010; Hu and Hao 2011; Xu et al. 2015; Wei et al. 2022). Amongst the Chinese members of subsect. Primula Petiolares Chartacea , the new species, is morphologically most similar to P. arunachalensis and P. fenghwaiana in its bud-scales lacking at anthesis, slender petioles, rounded blades, and scape shorter than or equal to pedicels, but can be recognized by almost absent rhizomes, morphological features of leaves, inflorescences, and flowers. Further morphological comparisons among P. wolongensis , P. arunachalensis and P. fenghwaiana are shown in Table 1 .

Figures

Figure 2. Primula wolongensis sp. nov. A habitat B habit C whole plant D roots and second-year buds E leaves F bracts G scape H thrum flower I pin flower J calyx in fruit K capsule.

Figure 4. Type sheet of Primula wolongensis.