Lysimachia ailaoshanensis (Primulaceae), a new species from Yunnan, China Author Yan, Hai-Fei State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China Author Hao, Gang South China National Botanical Garden, Guangzhou 510650, China text PhytoKeys 2024 2024-09-17 246 277 282 journal article 10.3897/phytokeys.246.130838 Lysimachia ailaoshanensis G. Hao & Y. F. Yan sp. nov. Figs 1 , 2 Type. China . • Yunnan Province , Jingdong Yi Autonomous County , Xujiaba , near Damenkou ; 24 ° 31 ' N , 101 ° 00 ' E ; alt. 2363 m ; 14 Aug. 2020 ; Hai-Fei Yan et al. Y 2020286 ( holotype : IBSC ! barcode IBSC 1021506 ; isotypes : IBSC ! barcode IBSC 1025535 , IBSC 1025536 ) . Diagnosis. Lysimachia ailaoshanensis is most similar to L. chenopodioides Watt ex Hook. f. and L. remotiflora C. M. Hu , but differs from L. chenopodioides in narrower lanceolate leaf blade and longer pedicel, and longer stamens and styles, and from L. remotiflora in narrower leaf blade and longer stamens. Description. Herbs annual, glabrous, 18 to 58 cm tall. Stems erect to ascending-erect, quadrangular, branches usually few above middle. Leaves alternate; petiole 1–2.8 cm long, narrowly winged; leaf blade narrowly lanceolate, 1.8–6.0 × 0.5–1.5 cm , sparsely dark purple or brown glandular punctate, base attenuate, apex acuminate to acute. Pedicel 0.5–2 cm long. Flowers in axils of upper leaves, always forming a raceme of 5–18 cm , lax. Calyx lobes lanceolate, 4.5–5.5 mm long, split nearly to base, dark purple or black glandular striate outside, apex obtuse to subacute. Corolla white or pink; tube ca. 1 mm long; lobes oblong-spatulate, 4.5–5 mm long, dark purple glandular striate, apex obtuse. Stamens ca. as long as to slightly shorter than corolla lobes; filaments adnate to base of corolla lobes, free parts ca. 4.0 mm; anthers ovate, dorsifixed, ca. 0.5 mm . Ovary glabrous; style ca. 4.5 mm . Capsule globose, ca. 4 mm in diameter, glabrous. Distribution and habitat. The new species is presently known only from the type locality in Yunnan Province , Jingdong Yi Autonomous County (Map 1 ). It grows at the edge of secondary mixed-evergreen forests. Map 1. Location of the population of Lysimachia ailaoshanensis in Jingdong, Yunnan. Phenology. Flowering from June to August, fruiting from July to August. Etymology. The new species is named referring to the type locality where the new species occurs, Ailaoshan National Nature Reserve, Yunnan , China . Conservation status. Based on our field investigations in Jingdong Yi Autonomous County and adjacent areas in the past three years, only one population with only five individuals of the new species have been found in an area of 10 km 2 in Jingdong Yi Autonomous County. Moreover, the local habitat is under threat by road construction and tourism development. Therefore, the conservation status of the new species is assessed as Critically Endangered ( CR ) (B 2 a & bi, iii), according to the guidelines for using the IUCN Red List Categories and Criteria ( IUCN Standards and Petitions Committee 2024 ). Additional specimens examined ( paratype ). China . The same locality as holotype , 7 August 2023 , Hai-Fei Yan Yan 2023054 (IBSC! barcode IBSC 1025537, IBSC 1025538). Relationship with similar species. Based on the classification of Lysimachia by Handel-Mazzetti (1928) and Chen and Hu (1979) , the new species clearly belongs to Lysimachia subg. Palladia sect. Chenopodiopsis Hand. - Mazz., which is characterised by leaves alternate, racemes sparsely flowered or solitary in axils of upper leaves, filaments free, adnate to middle of corolla, and styles usually shorter than corolla. Approximately eight species were recognized in this section, mainly distributed in southwestern China and adjacent regions (e. g., Bhutan , India , Kashmir, N. Myanmar , Nepal , Pakistan ), and a few outliers in Thailand , the Mediterranean coast, and southeastern Africa ( Handel-Mazzetti 1928 ; Chen et al. 1989 ; Hu and Kelso 1996 ). The new species is morphologically similar to L. chenopodioides and L. remotiflora , but is distinctive in its leaf shape and heights of stamens and styles (see Table 1 , Figs 1 – 3 ). Table 1. Main morphological differences between Lysimachia ailaoshanensis and two similar species.

Features	L. ailaoshanensis	L. chenopodioides	L. remotiflora
Petiole length	1–2.8 cm	0.5–1 cm	ca. 1.1 cm
Lamina shape	narrowly lanceolate	ovate to rhomboid-ovate	ovate-lanceolate
Pedicel length	0.5–2 cm	1–2 mm	1.5–2.5 cm
Filament length	4.5–5 mm	1–1.5 mm	1–1.5 mm
Style length	4.5 mm	1.5 mm	2.5 mm

Figure 1. Lysimachia ailaoshanensis G. Hao & Y. F. Yan , sp. nov. A habit B abaxial (right) and adaxial (left) surfaces of a leaf C flower D calyx lobes E dissected corolla F pistil and its stigma (enlarged) G young fruit with persistent calyx. Drawn by Yun-Xiao Liu from the holotype. Figure 2. Living plant of Lysimachia ailaoshanensis G. Hao & Y. F. Yan , sp. nov. A habitat B habit C leaves on abaxial (right) and adaxial (left) surfaces D flower (lateral view) E corolla F pistil G abaxial (left) and adaxial (right) sides of a calyx lobe. Photographed by Hai-Fei Yan. Figure 3. Holotypes of Lysimachia ailaoshanensis and two of its allies A L. ailaoshanensis B L. chenopodioides C L. remotiflora .