Lycoris wulingensis, a dwarf new species of Amaryllidaceae from Hunan, China

Abstract Lycoris wulingensis S.Y. Zhang, a new species from Hunan Province (central South China), is described and illustrated. This new species is a fertile diploid plant and its karyotype is 2n = 22. It is most similar to L. × haywardii in morphology, but the latter is a hybrid species and distributed in East China and the plant is much larger. Amongst the original species, L. wulingensis is similar to L. radiata, but differs from it in its flowers being rose-red (vs. red) and stamens and tepals are nearly the same length (vs. stamens significantly longer than tepals).

Although there were 43 taxa names of Lycoris in the International Plant Name Index (IPNI, https://www.ipni.org/), Hsu et al. (1994) researched and revised the species taxonomy in this genus, based on hybridisation experiments, cytology and morphology and only recognised 20 species and seven varieties. In Korea, Kim revised native Lycoris and published two new species, i.e. L. flavescens and L. uydoensis (Kim 2004). Recently, three new species of Lycoris have been discovered and reported in China, namely L. hunanensis (Quan et al. 2013), L. × hubeiensis (Meng et al. 2018) and L. tsinlingensis (Lu et al. 2020).
During the long-term investigation and collection of Chinese Lycoris plant resources over many years, we accidentally discovered this dwarf unique Lycoris in the Wuling Mountains area (Hunan Province) in 2016. After four years of observation and cultivation, we confirm that it is a new species and it is described here.

Materials and methods
To observe and compare morphology characters, about 270 bulbs from nine populations (Table 1) of the putative new species and its relatives (L. radiata and L. × haywardii) were collected and brought back for cultivation in August 2015 or 2016. In 2019, the morphological data for bulb diameter, leaf length and width and flower size (tepal length) were measured and recorded from cultivated populations. In 2020, bulb roots were induced by burying in wet sand and the chromosome number was observed using the methods described by Chen and Li (1985). Pollen vitality was tested using the TTC staining method (Oberle and Watson 1953). All statistical analyses were performed in SPSS ver. 19.0.  Table 2) and it is restricted to north-western Hunan Province (Fig. 5).
Phenology. Flowering from mid-July to late-August; fruiting in September; and leaves growing in mid-September.
Distribution. Lycoris wulingensis is distributed in the east of Wuling Mountains and its surrounding areas, such as Cili, Linli, Li, Taoyuan and Yongding Counties (Fig. 5).
Habitat. Lycoris wulingensis is partial to grow on the edge of forest roads, farmland or riverside beaches, usually under deciduous trees (such as Alangium chinense and Pterocarya stenoptera) and accompanied by Pinellia ternata, Commelina communis,  Flower rose-red, tepals 2.5-2.8 cm long, apex slightly reversed and slightly undulate, stamen 3-3.5 cm long.
Conservation status. Compared with other species in the Lycoris, the distribution range of Lycoris wulingensis is relatively narrow. Based on preliminary  investigation, we found only four large populations and some sporadic distribution points. However, considering the lack of in-depth investigation and also considering that some populations may occur in other similar habitats, we classified its conservation status as Data Deficient (DD), according to the IUCN Red List Criteria (IUCN 2019).

Discussion
After four years of cultivation and observation, we found that the plant size of Lycoris wulingensis was consistently small (Figs 3, 4). Amongst different wild populations and even under different cultivation conditions, its leaf length was always less than 27 cm, bulb diameter was about 2-3 cm and flower tepal length was less than 3 cm (Figs 3, 4). To our knowledge, the body size of this new species is the smallest in Lycoris (Hsu et al. 1994;Ji and Meerow 2000). The flowers of L. wulingensis are rose-red and their filaments are nearly equal to tepals in length, which is most similar to L. × haywardii. However, previous hybridisation experiments, molecular studies and field investigations have shown that L. × haywardii is a hybrid species which is only distributed in eastern China (the overlapping area of its two parents, L. radiata and L. sprengeri) (Hsu et al. 1994;Shi et al. 2006), while L. wulingensis is now known to be distributed in the east of Wuling Mountains and its surrounding areas in north-western Hunan Province, central South China. In addition, possibly due to the scape of L. sprengeri (one parent) being tall and strong, the scape of L. × haywardii is stronger and longer than that of L. radiata and L. wulingensis (Figs 3,4) and the flower of L. × haywardii is about twice the size of L. wulingensis (Figs 3, 4). In terms of leaf morphology, L. wulingensis and L. radiata both have narrow dark green leaves with a clear white band in the centre. However, there are many obvious differences between these two species in flower characters, such as the colour of the former being rosered and the stamen length is about equal to the petal length, while the latter's are red and stamens are about twice as long as the tepals. Thus, it is easy to distinguish L. wulingensis from its related species by plant size, floral characters and distribution range (Table 2).
Initially, we speculated that L. wulingensis was a haploid type of L. radiata and its dwarfism characters were possibly induced by the loss of half of its chromosomes. However, its chromosome number is 2n = 22 (Fig. 1J), which is similar to the original species of L. radiata, L. sprengeri and L. sanguinea (Hsu et al. 1994;Hori et al. 2006). TTC staining showed that the vitality of its pollen was normal (Fig. 1K). Furthermore, L. wulingensis can sexually produce offspring by seeds in wild habitats and under cultivated conditions and the seeds can also germinate and develop into seedlings. Therefore, we suppose that L. wulingensis is likely to be an original diploid species, which possibly has high value in terms of horticultural breeding.