Lysimachia danxiashanensis W.B.Liao, Q.Fan & G.D.Tang, 2024

Zhang, Xing-Yue, Dai, Jing-Min, Fan, Qiang, Chen, Zai-Xiong, Tang, Guang-Da & Liao, Wen-Bo, 2024, Lysimachia danxiashanensis, a new species of Primulaceae from Guangdong, China, PhytoKeys 237, pp. 257-268 : 257

Lysimachia danxiashanensis W.B.Liao, Q.Fan & G.D.Tang sp. nov.

Figs 2 , 3

Diagnosis.

Lysimachia danxiashanensis can be distinguished from L. congestiflora by its purple-red plants (vs. green), petiole without wings (vs. narrowly winged), corolla lobes yellow with serrations on upper half (vs. dull red at base with entire margin) and calyx with orange glandular (vs. without glandular) (Fig. 4 ).

Type.

China. Guangdong Province, Danxiashan National Park , 25°0'N, 113°37'E, 311 m a.s.l., 12 May 2023 (fl.), Xing-Yue Zhang, Zai-Xiong Chen DNPC 3801 (holotype SYS!; isotypes CANT! SYS!) .

Description.

Perennial herb, 10-28 cm tall. Stems prostrate, rooting at nodes, upper part ascending, purplish-red, terete, with dense white multicellular hairs. Leaves opposite, upper 2 or 3 pairs usually crowded, papery, ovate to broadly ovate or oval, wavy margin, 1.6-3.8 × 1.2-2.4 cm, apex acute, base broadly cuneate; adaxial surface dark green with antrorse strigose, abaxial surface purple-red, with strigose and densely pilose along the mid-rib vein; lateral veins 2-4-paired; petiole without wings, 0.5-2.7 cm, densely villous. Racemes terminal, abbreviated, capitate, 5-9 flowered; pedicel 3-5 mm long, densely pilose. Calyx 5, parted nearly to base; lobes lanceolate, 2-2.5 × 7-8.5 mm long, sparsely orange glandular on both surfaces, pilose outside. Corolla yellow; tube 1.5-2 mm; lobes 5, obovate-elliptical, 3-5 × 9-10 mm, serrate on upper half, apex acute to obtuse, abaxially glabrous, sparsely orange-red glandular, adaxially glabrous with orange-reddish glandular. Stamens 5, filaments glabrous, connate basally into a 2-3 mm high tube, free parts 2.8-4.5 mm; anthers ovate-lanceolate, dorsifixed, opening by lateral slits, ca. 2.8 mm long. Ovary white, terete, apex puberulous, glabrous at lower part; style glabrous, 6-8 mm long, stigma obtuse with papillae. Capsule subglobose, green, apex puberulous, 3-5 mm in diam.

Phenology.

The flowering of Lysimachia danxiashanensis is from May to June; and the fruiting in June.

Distribution.

Lysimachia danxiashanensis is currently known only from the type locality, Danxiashan National Nature Reserve, Guangdong, China.

Habit.

Lysimachia danxiashanensis was observed to grow on wet rocks of Danxia landform at elevations 270 to 320 m.

Etymology.

The specific epithet refers to the type locality, Danxiashan National Nature Reserve in Guangdong Province, China.

Local name.

The Chinese name of the new species is here given as 丹霞山过路黄 ( Dān xiá Shān Guò Lù Huáng).

Provisional conservation status.

Endangered (EN). In the past two years, we have conducted several field investigations on the Danxia landscapes in Guangdong Province, with only four populations of Lysimachia danxiashanensis being found in Danxiashan National Nature Reserve and the number of mature individuals is stable (total <200 individuals); However, its habitat is on the side of the road, which is vulnerable to human disturbance. L. danxiashanensis is regarded as Endangered (EN) according to D (the number of mature individuals in the population <250) ( IUCN Standards and Petitions Committee 2022).

Additional specimens examined

(paratypes). China, Guangdong: Danxiashan National Park, 25°0'N, 113°38'E, 298 m a.s.l., 12 June 2023 (fr.), Jie-Hao Jin DNPC 3803 (SYS!); Danxiashan National Park , 25°0'N, 113°38'E, 14 August 2023, Qiang Fan, Jie-Hao Jin & Li-Juan Liao DNPC 3845 (SYS!) .

Figures

Figure 2. Lysimachia danxiashanensis W. B. Liao, Q. Fan & G. D. Tang, sp. nov. A habit B flowering branch C inflorescence D abaxial and adaxial views of leave E lateral view of flower F dorsal view of flower G adaxial side of corolla lobes H stamens I immature capsule J abaxial (1 st, 2 nd, 5 th) and adaxial (3 rd, 4 th) views of calyx lobes K pistil and densely pilose pedicel L stigma M cross-section of ovary (Photographers: A, C, D, I by Xing-Yue Zhang; B, E, F by Qiang Fan; G, H, J-M by Jing-Min Dai).

Figure 3. Lysimachia danxiashanensis W. B. Liao, Q. Fan & G. D. Tang, sp. nov. A habit B abaxial (left) and adaxial (right) views of leaf C adaxial side of corolla lobes D lateral view of flower E dorsal view of flower F stamens G pistil and stigma H fruit I adaxial (left) and abaxial (right) views of calyx (Drawn by Rong-En Wu).

Figure 4. Morphological differences between L. congestiflora and L. danxiashanensis A L. congestiflora B L. danxiashanensis 1 plants 2 corolla lobes 3 calyx lobes 4 petiole (Photographers: A- 1 by Wan-Yi Zhao A 2 - 4 by Xin-Xin Zhu B 1, 2, 4 by Xing-Yue Zhang B- 3 by Qiang Fan).