Monotropa callistoma Ze Wei, Li J. Liu & Bing Liu, 2026

Monotropa callistoma Ze Wei, Li J. Liu & Bing Liu sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2 , 6 View Figure 6

Diagnosis.

Monotropa callistoma is characterised by its 4 or 5 glabrous petals (apically orange and basally white), 8–10 stamens with glabrous filaments, flowering period starting from March and nodding capsule at maturity. It is morphologically most similar to M. uniflora and Monotropastrum humile , but differs by the characters summarised in Table 2 View Table 2 .

Type.

China. • Hunan Province: Shaoyang City, Xinning County, Shunhuang Mountain , 1560 m elev., 29 March 2021, Xuan Jing, Xie Gan, Wei Ze & Ouyang Wenxiang 60 ( holotype: PE [ PE 02432010 !]) (Fig. 5 View Figure 5 )

Description.

Herbs, fully mycoheterotrophic. Plants lacking chlorophyll, white when fresh, turning black upon drying. Stems erect, simple, unbranched, 9–15 cm tall, fleshy. Roots thick, densely branched, forming a bird’s-nest-like mass. Leaves scale-like, erect, alternate, oblong to broadly lanceolate, 12–18 mm long, 4–6.5 mm wide, apex obtuse, glabrous, margin nearly entire. Flower solitary, terminal, campanulate, 2–3 cm long, 1–1.5 cm in diameter. Sepals 4 or 5, scale-like. Petals 4 or 5, distinct, obovate-oblong, 2–2.5 cm long, 5–10 mm wide, fleshy, glabrous, orange in the apical one-quarter and white in the basal three-quarters, margin entire. Stamens 8–10; filaments glabrous; anthers yellow. Ovary glabrous, with parietal placentation, 1 - loculed; style 5–7 mm long; stigma expanded, funnel-shaped. Berries ellipsoid-globose, with the fruiting pedicel becoming curved and nodding at maturity.

Phenology.

Flowering from March to June; fruiting from April to July.

Distribution and habitat.

Currently known only from the type locality in Hunan Province, China. It grows in dense, humid broad-leaved forests at an elevation of around 1560 m, in association with ectomycorrhizal fungi. However, according to records from PPBC ( https://ppbc.iplant.cn/) and iNaturalist ( www. inaturalist. org /), it has also been reported from Guizhou, Yunnan, Guangxi, Sichuan, Hunan, Xizang and Chongqing. As these records are based solely on photographs without supporting herbarium specimens, they are considered unverified and serve only as references.

Vernacular name

(Chinese name). 美冠水晶兰 (měi guān shuǐ jīng lán).

Etymology.

The specific epithet callistoma is derived from the Greek calli - (beautiful) and - stoma (mouth), alluding to the aesthetically pleasing form and colouration of the corolla orifice.

Preliminary conservation status.

Data Deficient ( DD). This species is currently known only from a single population. Further field surveys are needed to assess its full distribution and population size. The type locality is within a protected scenic area, which may offer some level of protection.

Additional specimens examined

( Paratype). China. • Hunan Province: Shaoyang City, Xinning County, Shunhuang Mountain , 1560 m elev., 29 March 2021, Xuan Jing, Xie Gan, Wei Ze & Ouyang Wenxiang 60 ( PE 024320009 !) .