Mycetia saxicola Z. Q. Song & D. X. Xu, 2025

Mycetia saxicola Z. Q. Song & D. X. Xu sp. nov.

Figs 1 View Figure 1 , 5 岩生腺萼木 View Figure 5

Type.

China. Yunnan Province, Malipo County, Tianbo Town, Yaowanggu , 23.022556, 104.825471, in limestone hills, elev. 1100 m, 27 November 2023, Z. Q. Song & B. Y. Zhang JZ 20231427 ( holotype: IBSC 1083200 ; Suppl. material 3) GoogleMaps .

Description.

Shrubs, 0.5–2 m tall, sometimes with little-branched; bark straw-yellow and corky at the upper parts, brown at the lower parts, but green at the apical parts; branches mostly ca. 4 mm in diameter. Leaves simple, opposite; petiole 1.5–4 cm, glabrous; blade 9–22 × 3–8 cm, narrow elliptic or lanceolate, cuneate at base, gradually long acuminate at the apex, stiff chartaceous or subleathery, glabrous on both surfaces, discolourous, deep green above and much paler green below; secondary nerves 9–11 pairs, alternate, subparallel, markedly curved at the margin. Stipules interpetiolar, linear, 4–6 × 1–2 mm, green at first and then turning brown, often deciduous. Inflorescences usually less than 1 cm long, directly borne on the stem (i. e., cauliflorous), trichotomously cymose, with a very short ( 1–2 mm long) peduncle, few-flowered, usually less than 6 flowers, sometimes 2–4 flowers fasciculate directly on the stem (peduncle absent); bracts and bracteoles lanceolate, ca. 1 mm long, without glands, caducous; pedicels very short, ca. 1.5 mm long. Flowers bisexual, heterodistylous, ca. 5 mm long. Calyx nearly hemispheric, ca. 2 mm high, subglabrous; lobes 5, persistent, deltoid-lanceolate, ca. 1.5 mm long, ca. 1 mm wide at base, with two sessile glands each sinus; glands deciduous. Corolla yellow, turning whitish at the end of the blooming period, urceolate, slightly swollen at base; tube ca. 3–4 mm long, subglabrous outside, pilose at middle position inside; lobes deltoid-ovate, acute, ca. 1.5 mm long, recurved. Stamens 5, subsessile; anthers situated at the base of the corolla tube for the long-styled flowers and situated at the upper of the corolla tube for the short-styled flowers, oblong, dorsifixed, ca. 1 mm long. Ovary 2 - celled, with numerous ovules in each cell; style simple, slender, ca. 1.8 mm long for the long-styled flowers, ca. 0.5 mm long for the short-styled flowers; stigma bifid, linear, ca. 1.8 mm long for the long-styled flowers, ca. 1.2 mm long for the short-styled flowers. Fruits 2 - chambered, subglobose, green and 3–3.5 mm in diameter when immature, turning white and baccate when mature, ca. 6–7 mm in diameter, crown with persistent calyx lobes. Seeds numerous, angled, ca. 0.3–0.5 mm across, slightly brown at first and turning shiny black when mature; testa granular.

Phenology.

Flowering from August to September and fruiting from September to February.

Distribution and habitat.

Mycetia saxicola is currently known from Malipo County and Hekou County, Yunnan Province, China (Fig. 5 View Figure 5 ), and it grows in the understory of forests in limestone regions at 150–1100 m elevation. It is probable that this species will be found in northern Vietnam in the future.

Etymology.

The specific epithet saxicola is derived from the Latin saxum (rock) and the suffix - cola (dweller), emphasizing the limestone habitat, a distinctive and noteworthy feature of this new species.

Preliminary conservation status.

This new species is known from multiple localities in two counties in Yunnan Province, in both unprotected and protected limestone areas. Thus, the species may be considered a Near Endangered ( NT) species under the IUCN categories ( IUCN 2024).

Additional specimens examined.

China. Yunnan Province, Hekou County, Nanxi Town, Longyinchong , 22.685076°N, 104.019973°E, in limestone area, elev. 950 m, 5 September 2025, B. Y. Zhang, Q. L. Yan & X. K. Xiong ZY 202518 ( IBSC) GoogleMaps ; Yunnan Province, Hekou County, Nanxi Town, Maduoyi , 22.639901°N, 103.985103°E, in limestone area, elev. 323 m, 6 September 2025, B. Y. Zhang, Q. L. Yan & X. K. Xiong ZY 202520 ( IBSC) GoogleMaps ; Yunnan Province, Hekou County, Nanxi Town, Huayudong , 22.674730°N, 103.940051°E, in limestone area, elev. 141 m, 6 September 2025, B. Y. Zhang, Q. L. Yan & X. K. Xiong ZY 202521 ( IBSC) GoogleMaps ; Yunnan Province, Hekou County, Nanxi Town, Xiaoping , 22.681047°N, 103.903411°E, in limestone area, elev. 735 m, 7 September 2025, B. Y. Zhang, Q. L. Yan & X. K. Xiong ZY 202523 ( IBSC) GoogleMaps .