Acronema handeloides X. D. Ma & C. F. Song, 2025

Acronema handeloides X. D. Ma & C. F. Song sp. nov.

Figs 3 View Figure 3 , 4 View Figure 4

Diagnosis.

Acronema handeloides has flowers and fruits similar to A. handelii and A. sichuanense but differs from these latter in its frequently branched stems (1–2 branches), fewer number of umbel rays and umbellule rays, 1–3 bracteoles, and variable shape of basal leaves. These three species are readily distinguishable by key morphological characteristics, as detailed in Table 3 View Table 3 and Fig. 2 View Figure 2 .

Type.

China • Yunnan: Kunming City, Luquan County, Wumeng Township, Jiaozi Mountain , 26.0795°N, 102.8480°E, in the moss understory of the Rhododendron forest, 15 August 2025 (fl. & fr.), X. D. Ma & Y. X MXD 370 ( holotype: NAS!; isotype: NAS!) GoogleMaps .

Description.

Annual to biennial herbs, glabrous, 1–10 cm tall. Roots spherical to ellipsoidal, 3–4 mm in diameter. Stems slender, with 1–2 lateral branches or unbranched. Basal leaves: petiole 8–30 mm, sheath narrow; leaf blade polymorphic, 1–1.5 cm long, 1.3–2 cm wide; when simple, blade broadly ovate, base truncate to slightly cordate, margin irregularly serrate, or trifid to tripartite, lobes obovate, apex trifid; when trifoliolate, leaflets short-petiolulate, apex trifid, lobes shallowly 1–3 - lobed at apex; when 2 - ternate, pinnately compound, ultimate segments obovate, apex trilobed. Cauline leaves similar to basal ones, occasionally simple and lanceolate. Peduncle 1.5–2.5 cm long; bracts 1 or absent, lanceolate; rays 2–5, 5–20 mm long, subequal; bracteoles 1–3, subulate; umbellules 2–5, 4–9 mm long, subequal. Calyx teeth subulate, conspicuous. Petals purplish red, ovate to obovate, ca. 1 mm long; apex linear-subulate, papillate, ca. 1 mm long. Fruit broadly ovoid, ca. 1 × 1.5 mm, base cordate, glabrous; primary ribs filiform, inconspicuous; vittae 1–2 in each furrow, 2 on the commissure.

Phenology.

Flowers are observed from July to August, and fruits from August to September.

Etymology.

The species epithet ‘ handeloides ’ is derived from the combination of “ handel ” (from Acronema handelii ) and the suffix “ - oides ” (meaning “ resembling ”), indicating the morphological similarity of this new species to A. handelii . The Chinese name “ 拟中甸丝瓣芹 ” (nĭ zhōng diàn sī bàn qín) is a direct translation from the epithet, used to maintain nomenclatural consistency and avoid ambiguity.

Distribution and habitat.

This new species is currently only found in the moss understory of the Rhododendron forest at 3700 m on Jiaozi Mountain in Luquan County, Kunming, Yunnan (Fig. 5 View Figure 5 ).

Additional material examined ( paratype).

China • Yunnan: Kunming City, Luquan County, Wumeng Township, Jiaozi Mountain , 26.0795°N, 102.8480°E, on the moss understory of the Rhododendron forest, 31 August 2024 (fr.), X. D. Ma & H. R. Zhuang MXD 290 ( NAS!) GoogleMaps .

Conservation status and discussion.

Following the description of A. crassifolium by Wang Huanchong in 2013, A. handeloides represents another new species of Acronema discovered on Jiaozi Mountain. Located near Kunming, Jiaozi Mountain is renowned as “ the premier mountain of central Yunnan ” and has been increasingly developed for tourism due to its scenic landscapes and winter snowfall ( Chang 2019; Zhang et al. 2020). This development poses potential threats to understory habitats through intensified human activities. Acronema species typically occur in moist, moss-rich understories at high altitudes, representing a highly specialized ecological niche that is particularly vulnerable to disturbance in visited areas.

To date, Acronema handeloides is documented only from Jiaozi Mountain, with no prior collection records. Field observations indicate that the new species exhibits low fruit abortion rates in the wild, implying successful reproductive capacity under natural conditions. Despite this, available data on its full distribution and population trends remain incomplete. Therefore, in accordance with the IUCN Red List criteria ( IUCN 2024), we recommend that the conservation status of A. handeloides be preliminarily assessed as Data Deficient ( DD) to reflect current uncertainties.