Jasminum parceflorum Kai Zhang & D.X. Zhang, 2020

Zhang, Kai, Wu, Mingsong, Pan, Bo, Zhou, Lianxuan & Zhang, Dianxiang, 2020, Jasminum parceflorum (Oleaceae), a new species from southern Yunnan, China, PhytoKeys 146, pp. 109-115 : 109

Jasminum parceflorum Kai Zhang & D.X. Zhang sp. nov. Figs 1 , 2

Diagnosis.

Jasminum parceflorum is morphologically similar to J. pierreanum Gagnep. and J. rarum Kerr, but can be distinguished by its linear calyx lobes, dry calyces without ridges, terminal 1 (or 3)-flowered cymes and axillary solitary flowers.

Type.

CHINA. Yunnan Province: Xishuangbanna Prefecture, Jinghong City, Yinchang Mountain, 21°59'6.48"N, 101°14'4.22"E, 1218 m a.s.l., 18 July 2018, Kai Zhang & Mingsong Wu 00581 (holotype: IBSC!; isotypes: IBSC!, HITBC!).

Description.

Shrubs, scandent, evergreen, 1-5 m tall. Branches grayish yellow, terete; branchlets green, slender, pubescent, slightly compressed and inconspicuously grooved when young. Leaves opposite, simple; petiole 1-3 mm long, slightly twisted, articulate near middle, sulcate adaxially, pubescent; leaf blade ovate or lanceolate, sometimes broadly ovate, 2.8-6.3 cm long, 0.9-2.5 cm wide, papery, with entire margin, slightly revolute, base broadly cuneate, rounded or subtruncate, sometimes cuneate or subcordate, slightly oblique, apex acuminate to caudate-acuminate, adaxially pubescent along midvein, and sparsely pubescent near apex when young, abaxially yellow glandular dotted and vein axils with hair tufts; midvein slightly impressed adaxially, elevated abaxially, lateral veins 3-6 pairs, slightly elevated on both surfaces, arcuate-ascendant, anastomosing near margin. Flowers 1 (or 3) in terminal cymes, solitary in leaf axils, dimorphic. Peduncle 1-9 mm long, slightly pubescent. Bracts subulate-filiform, 2-3 mm long, glabrous. Pedicel 1.1-1.6 cm long, glabrous. Calyx campanulate, glabrous; tube 3-4 mm long; lobes 5, linear, (2-) 2.5-4 (-4.5) mm long. Corolla white, salverform; tube 1.3-2.3 cm long, ca. 1.5 mm in diam; lobes 5, lanceolate, 8-11 mm long, 2-3 mm wide, apex argute. Thrum flowers: stamens 2; filaments ca. 1 mm long, glabrous; anthers 12.7-13.6 mm above base of corolla tube, 6.1-7 mm long; stigma 1.5-2.4 mm long, 2-lobed; style filiform, 3.9-5 mm long, glabrous; ovary 0.9-1 mm long, glabrous. Pin flowers: stamens 2; filaments ca. 1 mm long, glabrous; anthers 10.8-11.7 mm above base of corolla tube, 5.4-5.6 mm long; stigma 1.9-2.9 mm long, 2-lobed; style filiform, 13.4-19 mm long, glabrous; ovary 0.9-1 mm long, glabrous. Fruits globose or subglobose, 8-9 mm in diam.

Phenology.

Flowering from July to August, fruiting from September to November.

Distribution and habitat.

Jasminum parceflorum is currently found in Mengla County and Jinghong City, Xishuangbanna Prefecture, Yunnan Province, China (Fig. 3 ). It grows in tropical evergreen forests on slopes of limestone mountains, never occurring in open areas such as mountain ridges and forest edges.

Conservation status.

Only two populations of the new species were found in Xishuangbanna Prefecture, Yunnan Province, although it may be distributed in adjacent limestone areas. Each population has no more than 200 mature individuals which only occur in limestone forests. According to the IUCN Red List Categories and Criteria ( IUCN 2019), Jasminum parceflorum is assigned a status of Vulnerable (VU D1).

Etymology.

The specific epithet is derived from the fact that its mature individual has fewer flowers in comparison with most other jasmine species.

Additional specimens examined.

CHINA. Yunnan Province: Xishuangbanna Prefecture, Jinghong City, Yinchang Mountain, 15 July 2018, Kai Zhang & Mingsong Wu 00532, 00533 (IBSC!); same locality, 18 July 2018, Kai Zhang & Mingsong Wu 00582 (IBSC!); same locality, 12 July 2019, Kai Zhang & Lianxuan Zhou 01177, 01178 (IBSC!); same locality, 13 November 2019, Kai Zhang 01216 (IBSC!). Mengla County, Lvshilin, 21°54'36.80"N, 101°17'3.83"E, 614 m a.s.l., 13 November 2019, Kai Zhang 01215 (IBSC!).

Figures

Figure 1. Jasminum parceflorum. A flowering branch B branchlet C leaves (adaxial view and abaxial view) D vein axils with hair tufts (abaxial view) E stamens F pin flower G thrum flower H peduncle with bracts I calyx J pistil of pin flower K pistil of thrum flower L stigma. Drawn by Yunxiao Liu.

Figure 2. Jasminum parceflorum. A habitat B habit C branch with a thrum flower D branchlet E dissected corolla tubes, thrum flower (upper) and pin flower (lower) F fruiting branch G branches with pin flowers H calyx. Scale bars: 0.5 mm (D), 1 cm (E, F), 1 mm (H). Photos by Kai Zhang.

Figure 3. A Distribution of Jasminum parceflorum in Yunnan Province, China B view of Yinchang Mountain.