Herpetospermum motuoensis Y. S. Chen & B. Y. Zhang, 2025

Zhang, Bu-Yun, Liu, Hou-Zhou, Xu, Ye-Chun, Song, Zhu-Qiu & Chen, You-Sheng, 2025, Herpetospermum motuoensis (Cucurbitaceae), a new species from Xizang, China, Phytotaxa 697 (3), pp. 288-293 : 289-292

Herpetospermum motuoensis Y. S. Chen & B. Y. Zhang , sp. nov. ( Fig.1 )

Type: China, Xizang, Motuo county, Damu village , 29.4759°N, 95.4537°E, on the north slope, forest edge, alt. ca. 1380 m, 31 October 2023, B. Y. Zhang, Y. D. Xu, G. F. Liu et X. R. Zheng JZ 20231191 (holotype: IBSC1057724 ; isotypes: IBSC1057725 , IBSC1057726 , IBSC1057727 , IBSC1057728 , PE!, KUN!) .

Diagnosis: The new species is similar to Herpetospermum operculatum in habit, cordate-triangular leaf blades, ascendent ovules, immature fruit with 6–7 yellow-green stripes, mature fruit dehiscing through operculum, but can be distinguished by the inconspicuous bracts of male flowers, rounded to broad ovate, 1–1.5 mm long (vs. Prominent bracts of male flowers, linear-lanceolate to ovate, 8–12 mm long), petals subrounded to elliptical (vs. petals ovate to obovate), ovules 6 per locule (vs. ovules 8 per locule), stigma subrounded to broadly elliptic(vs. stigma oblongovate), fruits chartreuse, fusiform to ellipsoid-fusiform, glabrous (vs. fruits oblong to ellipsoid-fusiform, pubescent), Seeds irregular oblong hexagon, margin with protrusion at each corner (vs. Seeds ± round, margin with irregular acute erose).

Description. Dioecious lianas. Stems subglabrous, 2–6 m long, 1–4 mm in diameter. Tendrils 2–5 branched, puberulent, branch length unequal, one branch apparently thicker than others.

Leaves simple, petiole 1.7–6.0 cm long, subglabrous; leaf blades cordate-triangular, 2.5–11 cm long, 3.5–15 cm wide, papery, sparsely puberulent on both surfaces, usually 3–7 lobed, lobes oblong to triangular, margin minutely denticulate, apex acute to acuminate. Male inflorescence solitary, 7–21 cm long, 5–16 flowers; peduncle 2–10 cm, puberulent; bract inconspicuous, rounded to broad ovate, 1–1.5 mm long, caducous. Male flowers: pedicel 5–10 mm long; calyx tubes elongate, 2–3 cm long, cylindric at base, 2–3 mm in diameter, dilated at apex, widened to 8–12 mm in diameter, segments broadly ovate to triangular, apex mucronate, 2–4 mm long; corolla yellow, 5–8 cm in diameter, petals 5, subrounded to elliptical, 1.6–2.9 cm long, 2.3–3.9 cm wide, apex obtuse or abruptly mucronate; stamens 3, filaments glabrous, 5–7 mm long, inserted below the throat of the calyx tube, anthers 3, connate, 4–6 mm long, one 1–celled, two 2-celled, loculi linear; rudimentary ovary subulate, 4–5 mm long, base bulbous. Female flower solitary, pedicel 0.9–2.4 cm long; calyx tube elongate, 1.5–2.0 cm long, cylindric at base, 2–3 mm in diameter, dilated at apex, widened to 7–11 mm in diameter, segments ovate, triangular to subulate, apex tail-like; corolla as in male flowers; ovary 0.9–1.6 cm long, cylindric, sparsely puberulent, ovules 6 per locule, ascendent, styles 1.3–2.1 cm long, stigma 3, 2-lobed, subrounded to broadly elliptic, 3–4 mm long. Fruiting peduncle 4–9 cm long; immature fruit with 6–7 yellowish-green stripes, glabrous; mature fruit yellow, chartreuse, fusiform to ellipsoid-fusiform, 2.8–3.3 cm long, 8.8–10.3 cm wide, base cuneate, apex with rostrate operculum, fruit dehiscing through operculum and then releasing the seeds, operculum 1.5–1.8 cm in diameter, 0.7–1.1 cm long. Seeds irregular oblong hexagonal, compressed, 0.8–1.0 cm long, 1.2–1.5 cm wide, turning brownish black or black after maturity, margin with protrusion at each corner, these protrusions are easily worn out.

Etymology: Herpetospermum motuoensis is named after its type locality, Motuo county, Xizang Tibetan Autonomous Region, China.

darjeelingense and H. pedunculosum .

Vernacular name: —墨ȒṘĠE, mo tuo bo leng gua in Chinese Pinyin.

Phenology. Flowering from September to November, fruiting from October to January in the following year.

Distribution and habitat. Herpetospermum motuoensis is known only from Motuo county, Xizang. It grows in thickets and on forest edges between 1300–2500 m.

Conservation status: —The new species was found from five populations, all distributed in Motuo County. One population in Damu village, the population we investigated, includes only 4 individuals on roadsides near the village, and the population is likely to disappear due to road construction and reclamation of wasteland. The other four populations were discovered based on specimens and photo records, but none of the collectors and photographers described population size or threats. Since Motuo County is a poorly sampled territory, it is likely that there are still some undiscovered populations. Therefore, considering insufficient data of the new species to determine the threat status, we suggest that H. motuoensis should be treated as ‘Data Deficient’ (DD) according to the IUCN red list categories and criteria ( IUCN Standards and Petitions Subcommittee 2019).

Additional specimens examined: — CHINA. Xizang: Motuo county , elev. 1750 m, in broad-leaved forest on the hillside, 21 Aug. 1974, Qinghai-Xizang Plateau Expedition 74-4421 [ PE ( PE01178539 )] ; Motuo county, Gedang Village , elev. 2450 m, the shrub layer of evergreen broad-leaved forest, 6 Sept. 1982, B. S. Li & S. Z. Chen 0867 [ PE ( PE01179190 )] ; ibid, elev. 1940 m, 6 Oct. 1982, B. S. Li & S. Z. Chen 1431 [ PE ( PE01179188 )] ; Xizang, Motuo county, Damu village , on the north slope, forest edge, alt. ca. 1380 m, 11 Dec. 2021, H. Z. Liu MD20230246 ( IBSC) .

Figures

FIGURE 1. Herpetospermum motuoensis. A. Habitat; B. Habit; C. Tendril; D. Leaves; E. Male inflorescence; F. Top view of male flower; G. Back view of male flower; H. Longitudinal section of male flower; I. Top view of female flower; J. Back view of female flower; K. Longitudinal section of female flower; L. Fruits; M. Longitudinal section of fruit; N. Cross section of fruit; O. Seeds. A-O: all photos by BuYun Zhang based on the type, B. Y. Zhang, Y. D. Xu, G. F. Liu et X. R. Zheng JZ20231191 (IBSC).