﻿Lysimachiacavicola (Primulaceae), a new species from Guangxi, China

﻿Abstract Lysimachiacavicola (Subgen. Idiophyton, Primulaceae), a new species from Guangxi, China, is here described and illustrated based on morphological data. Although it shares similarities with L.microcarpa, L.fooningensis, and L.capillipes, there are distinguishing characteristics that set it apart. These include erect stems either solitary or in clusters of 1 to 2, herbaceous, terete, and densely glandular hairy. The leaves are either ovate or elliptical lanceolate, with inconspicuously reticulate veins. The petiole measures 2–4 mm in length covered with minute glandular hairy. The corolla is deeply parted, measuring 6–8 mm in length, with narrowly elliptic or narrowly oblong lobes that are 1–2 mm wide. The capsule is globose, measuring 2–3 × 2–3 mm, and possesses a chalky, brittle texture, which splits into 5-valved segments. The calyx of the plant appears yellowish-white during fruiting. This newly discovered species is endemic to limestone areas in Fengshan County, Guangxi, China.

The south-western limestone karst area is one of China's biodiversity hotspots.Multiple field works have been conducted in this area in recent years.During fieldwork in April 2021 to Fengshan County in Southwest of China, we discovered an unknown species glowed at the cave entrance.After several observations and consulting relevant literature (Hu and Kelso 1996), we confirm that the unusual plant is a species new to science of Lysimachia and is described below.

Morphology
The new species were described based on field observations that were conducted between April and August and examination of herbarium specimens at IBK and GXMI.Other related Lysimachia species were examined based on online images from the Kew Herbarium Catalogue (http://apps.kew.org/herbcat/gotoHomePage.do)and JSTOR Global Plants (http://plants.jstor.org/)and KUN, PE, IBSC and HITBC.Morphological characteristics that differentiate it from all other species in the genus of Lysimachia were used.The following characteristics were observed: stems, leaves, pedicels, flowers, receptacles, petals, stamens, gynoecium, carpels, size of flowers, size and shape of petals, number of stamens, and the shape of gynoecium and fruit.We also observed living plants of the new species during the flowering and fruiting period (April to July).
Descriptions were written from herbarium specimens.Measurements were made with a tape-measure and calipers.The structure of the indumentum and its distribution was observed and described under a dissecting microscope at magnifications of more than 20×.Additional information on locality, habitat, ecology, plant form and fruits were collected in the field and taken from herbarium labels.Conservation threat assessment followed IUCN Categories and Criteria (IUCN 2022).with distinct basifixation, and typically opening by apical pores, along with capsules dehiscing by valves.However, the new species can be easily distinguished by the following characteristics: stems solitary or clustered in 1-2, herbaceous and densely glandular; leaves ovate or elliptical lanceolate with inconspicuously reticulate veins; petioles 2-4 mm long that are minutely glandular hairy; capsules globose, 2-3 mm in diam., about the same length as the calyx.A more detailed morphological differences among the four species is presented in Table 1.Description.A perennial, herbaceous, 4-15 cm tall, aromatic when dry. Stems erect, solitary or 1-2 in clusters, terete and densely glandular.Leaves alternate: lamina ovate or elliptical lanceolate, 1.5-3(-4) × 0.5-1.6 cm, base attenuate, apex acuminate, glabrous except densely glandular hairy on midrid abaxially, vein-  lets invisible; petiole 2-4 mm long, minutely glandular.Flowers 5-merous, solitary, axillary at upper part of leaf axil; pedicel filiform, 2-4 cm long, sparsely glandular hairy; calyx green at flowering, lobes deeply parted, ovate-lanceolate, c. 2 mm long, glabrous except sparsely glandular abaxially and margin; corolla yellow, lobes deeply parted, narrowly elliptic or narrowly oblong, 6-8 × 1-2 mm, apex recurved downward, glabrous on both surfaces; filaments short, not more than half the length of anthers, filaments connate basally into c. 1 mm high ring, free parts 1 mm; anthers 4 mm long, basifixed, opening by apical pores.Capsule globose, 2-3 × 2-3 mm, chalky, brittle, split into 5-valved, calyx yellowish-white in fruiting.

Results and discussion
Phenology.Flowering in April-May; fruiting in June-July.Etymology.Fengshan, situated in the southwest of Guangxi, China, is a biodiversity hotspot known for its remarkable discoveries of new species (Nong et al. 2010;Wen et al. 2012;Li et al. 2019).One such species, Lysimachia cavicola, was found at the cave entrance in Fengshan, and the specific epithet is named after its habitat.
Distribution and habit.The new species is currently known only from the type locality from the southwest of Guangxi, China (Fig. 5).The new species mainly occurs at elevations of 800 m and it grows at the entrance of caves.
IUCN Red list category.Data Deficient (DD).Data available for the new species are still insufficient to assess its conservation status.According to the IUCN criteria (IUCN 2022), it is considered Data Deficient until further information becomes available.Although Lysimachia cavicola currently has relatively good growth, further collecting and monitoring is necessary to allow more conclusive estimations about its rarity and vulnerability for future conservation planning of this species.

Figure 1 .
Figure 1.Habitat of Lysimachia cavicola at the entrance of a limestone cave.Photographed by YN and K-J Y.

Figure 2 .
Figure 2. Line drawing of Lysimachia cavicola A flowering branch B flower C anthers D fruit E capsule F mid vein abaxially.Drawn by X-CQ.

Figure 3 .
Figure 3. Lysimachia cavicola A flowering plant B fruiting plant C flower (front view) D flower (back view) E flower (lateral view) F calyx (back view) G anthers H fruit I lateral (left) and front view (right) of capsule.Photographed by YN and K-JY.

Figure 4 .
Figure 4. Digital images of type specimens A Lysimachia cavicola B L. microcarpa C L. fooningensis D L. capillipes.