Lysimachia fenghwaiana G.Hao & H.F.Yan, 2023

Yan, Hai-Fei, Li, Jia-Xiang, Liu, Tong-Jian & Hao, Gang, 2023, Lysimachia fenghwaiana (Primulaceae), a new species from Hunan Province, China, PhytoKeys 220, pp. 75-82 : 75

publication ID	https://dx.doi.org/10.3897/phytokeys.220.99556
persistent identifier	https://treatment.plazi.org/id/97C37148-213C-5359-A0FC-80BD4F3E4081
treatment provided by	PhytoKeys by Pensoft
scientific name	Lysimachia fenghwaiana G.Hao & H.F.Yan
status	sp. nov.

Treatment

Lysimachia fenghwaiana G.Hao & H.F.Yan sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3

Type.

China. Hunan Province, Yueyang City, Pingjiang County, Lutou Forest Farm , 28°32'N, 113°55'E, alt. 421 m, 22 May 2022, Hai-Fei Yan and Chun-Lai Zhang Yan2022050 (holotype: IBSC! barcode IBSC0895001) GoogleMaps .

Diagnosis.

Lysimachia fenghwaiana is most similar to L. crista-galli Pamp. & Hand. -Mazz. and L. carinata Y.I.Fang & C.Z.Cheng, but is different in its leaf shape and arrangement of flowers. It further differs from L. crista-galli in the absence of calyx lobule spur, and differs from L. carinata in the black glandular striates in the corolla lobes (vs. punctate).

Description.

Herbs perennial, 20 to 70 cm tall. Stems erect, later arched to reclined, simple or shortly branched, initially covered with rust-coloured multicellular hairs, glabrescent. Leaves opposite; petioles 0.6-1.1 cm long, sparsely strigillose; blades broadly ovate, 1.2-2.8 × 0.8-1.8 cm, sparsely strigillose abaxially, densely short black glandular striate, base broadly cuneate, margin subentire, apex subacute to obtuse; midrib sunken abaxially, prominent abaxially when dry, secondary veins 3 or 4 pairs, veinlets inconspicuous. Flowers solitary or paired, in axis of apical leaves; pedicel 1-1.8 cm, glandular pubescent. Calyx 5-parted, green, lobes lanceolate, 5-6 mm long, abaxially cristate; crest widest at base, ca. 2 mm, black glandular striate, apex acute. Corolla yellow, tube ca. 2 mm long, lobes elliptic-lanceolate, ca. 11 × 4 mm, densely black glandular striate, apex obtuse. Stamens 5, filaments 3.2-3.5 mm long, connate basally into a tube, tube part 3.8-4.0 mm long, adnate to corolla tube, anthers oblong, ca. 1.8 mm long, dorsifixed, opening by lateral slits. Ovary ovoid, 1 mm long, glabrous, style ca. 7 mm long, stigma capitate. Capsules subspherical, ca. 5 mm in diameter, glabrous.

Distribution and habitat.

The new species is currently known only from the type locality in Hunan Province, i.e. Lutou Forest Farm in Pingjiang County, Yueyang City. It grows at the edge of secondary mixed-evergreen forests, or under open forest on the hillside, at an altitude of ca. 400-450 m a.s.l.

Phenology.

Flowering from May to June, fruiting from July to August.

Etymology.

The new species is named in honour of Prof. Feng-Hwai Chen, a Chinese plant taxonomist and horticulturist, who devoted all his life to the development of botanical gardens in China and made considerable contributions to the study of Primulaceae and Asteraceae .

Local name.

Simplified Chinese: 芦头过路黄; Chinese Pinyin: Lútou Guò Lù Huáng. “Lútou” means the flowers of Phragmites communis Trin. ( Poaceae ), which abundantly occurs locally. “Guò Lù Huáng” means plants of Lysimachia .

Conservation status.

Based on our field investigations in Yueyang City and adjacent areas (e.g. Hubei and Guangxi Provinces) in the past ten years, only one population with ca. 1000 individuals of the new species has been found in an area of 10 km2 in Lutou Forest Farm, Pingjiang County, Yueyang City. Moreover, the habitats are under threat from road construction and timber harvesting. Therefore, the conservation status of the new species is assessed as Critically Endangered (CR) (B2a & bi, iii), according to the guidelines for using the IUCN Red List Categories and Criteria ( IUCN Standards and Petitions Committee 2022).

Additional specimens examined

(paratypes). China. The same locality as holotype, 25 July 2021, Hai-Fei Yan et al. Yan 2021069 (IBSC!); The same locality as holotype, 4 June 2012, under forest, alt. ca. 500 m, Jiaxiang Li et al. 1855 (CSFI! barcode CSFI069374) .

Relationship with related species.

Based on the classification of Lysimachia by Handel-Mazzetti (1928) and Chen and Hu (1979), the new species clearly belongs to Lysimachia subgenus Lysimachia sect. Nummularia ser. Drymarifoliae Hand.-Mazz., which is characterised by filaments connate into a tube, adnate to the base of corolla tube; anthers shorter than filaments, opening by lateral slits; and plants producing coloured punctate or striate glands. Amongst this series, approximately six species constitute a group, highlighted by the calyx with crested ridges ( Handel-Mazzetti 1928; Chen et al. 1989; Zhou et al. 2015). The new species belongs to the group by having a crested calyx (Figs 1D View Figure 1 , 2G View Figure 2 ) and is morphologically similar to L. crista-galli and L. carinata , but is distinctive in its flowers occurring in the axis of the apical leaves, rather than in the axis of the middle and upper leaves in the latter two species. Further, from L. crista-galli , it differs in its cuneate leaf base and absence of corolla lobule spur (vs. leaf base cordate and calyx lobule spur present in L. crista-galli ); and from L. carinata , it differs by the shape of leaf lamina and corolla, i.e striate in L. crista (vs. punctate in L. carinata ) (see Table 1 View Table 1 ).

Whether the development of the crest to the calyx lobes, i.e. the winged keel of the calyx lobes, is a synapomorphy and those species constitute a monophyletic group in Lysimachia is uncertain, and further phylogenetic analysis should be undertaken to resolve this issue.