Hiptage stenopterum K.Tan & M.X.Ren, 2023

Zhang, Tong-Tong, Yang, Shu-Yun, Tan, Ke & Ren, Ming-Xun, 2023, A new species of Hiptage (Malpighiaceae) from northwest Yunnan (China) based on molecular and morphological data, PhytoKeys 232, pp. 45-57 : 45

Hiptage stenopterum K.Tan & M.X.Ren sp. nov.

Fig. 1

Diagnosis.

Hiptage stenopterum is most similar to H. incurvatum K.Tan & M.X.Ren by branchlets densely rusty tomentose (vs white to grey sericeous), leaf blades with 2 glands near the base (vs 10-16 glands), 10(-12) calyx glands [vs 4 (-6)], the posterior lateral wing oblanceolate (vs ovate), anterior lateral wings straight, lanceolate to linear (vs arcuate back to the middle, lanceolate).

Type.

China. Yunnan Province: Lushui City, Laowo River , 25°50′08″N, 98°54′28″E, 1071 m alt., 2 Apr. 2019, K. Tan 190402001 (Holotype: HUTB!; Isotype: HUTB!, IBK00450922!) .

Description.

Woody shrubs; young branches densely rusty tomentose, hairs adpressed, older twigs glabrous, with white or greenish lenticels, rounded, coarse warts dotted. Leaves opposite; stipules absent; petiole ca. 0.5 cm long, round, tomentose, with yellowish brown hairs, eglandular; leaf blades 4.0-12.0 × 2.0-5.0 cm, coriaceous, elliptic to oblong; young leaves densely rusty tomentose on both surfaces; mature leaves green, glabrous, base obtuse or broadly cuneate, margin plane, apex acuminate, abaxially often with 2 marginal glands near the base; lateral veins in 5-8 pairs, both surfaces prominently. Thyrses, terminal or axillary; main axis 4.0-13.0 cm long, rusty tomentose; peduncle 1.0-2.5 cm, rusty sericeous; bracteoles ca. 0.5 cm long, lanceolate. Flowers white to slightly pink; pedicels 1.5-2.0 cm long, densely rusty tomentose; sepals 5, 4.5-5.5 × 1.5-2.5 mm, elliptic to oblong, apex obtuse, margin slightly revolute, abaxially densely rusty tomentose, adaxially glabrous. Calyx glands 10(-12), prominent, not decurrent to the pedicel, often 1 pair of glands at base abaxially; two large, 2.3-2.8 × 0.8-1.2 mm, connate at the base, two smaller glands, 0.4-0.5 diam., rounded, adnate to the apex of the two larger glands separately; remaining glands small and free, 0.5-0.6 × 0.8-1.0 mm, oblong, attached to the margins of other sepals, occasionally one or two glands lacking. Petals 5, 1.0-1.5 × 0.8-1.2 cm, white to light white to pink, basally yellow, extremely reflexed, suborbicular, margin ciliate, claws ca. 1 mm long, base subcordate to rounded, apex roundish, abaxially densely white tomentose, adaxially glabrous. Stamens 10, basally fused or free, glabrous, differing in size, pollen sacs rimose; one larger, filament 10-12 mm long, yellowish green, circinate, anther oblong, 1.8-2.0 × 0.7-1.0 mm; 9 smaller stamens, filament 4-6 mm long; anthers oblong, 1-1.3 × 0.7-0.9 mm. Ovary ca. 2 mm in diam., ovoid, white to rusty tomentose; style 1, yellowish green, 10-13 mm long, slightly curved upwards, deflected either to the left or right side, glabrous; stigma apical. Mericarps 3, wings pink with yellow-green base, rusty sericeous, posterior lateral wing 3.8-4.5 × 0.7-0.9 cm, oblanceolate, apex roundish or lobed slightly, base obtuse, anterior lateral wings 2.4-3.0 × 0.3-0.6 cm, lanceolate to linear; areole ca. 4-6 mm, approximately triangular. Seeds angular-globose, 3-5 mm, dark yellow or brown.

Phenology.

Flowering in March and fruiting from March to May.

Etymology.

Its specific epithet reflects the long and narrow mericarp wings of Hiptage stenopterum .

Vernacular name.

Chinese: 狭翅风筝果(xiá chì fēng zhēng guǒ). The name’ xiá chì’ means its long and narrow wings, and 'fēng zhēng gǔo’ is the Chinese name of Hiptage .

Habitat and distribution.

H. stenopterum is only known from a valley of the Laowo River, a tributary of the Nujiang River, at an elevation ca. 1,000 m, near Lushui City, northwest of Yunnan Province, China (Fig. 2 ).

Conservation status.

Since the only known population of H. stenopterum is in an entrenched valley of Nujiang River in the northwest Yunnan Province, we have not discovered the wild population outside of the abovementioned place, information known about the population status and natural distribution range of the new species is very limited. Currently, only about 20 individuals are found in the valley. Therefore, we suggest that the new species H. stenopterum should be considered Data Deficient (DD) according to current IUCN Red List Categories and Criteria ( IUCN 2022).

Figures

Figure 1. Hiptage stenopterum A habit B flowering branch C flower in side view D flowers in frontal view E-G calyx glands (E calyx glands with secretions attracting ants) H young branch (showing densely rusty tomentose) I petals J winged mericarp K young leaf. Photos A, B by M. X. Ren, E by T. T. Zhang, and C, D, F-K by K. Tan.

Figure 2. Molecular phylogenetic tree of Hiptage based on ITS sequences. Bayesian posterior probability (PP) and ML bootstrap values (BS) are shown above branches as PP / BS (only shown if BS> 50 %).