Hiptage incurvatum K.Tan & M.X.Ren, 2019

Tan, Ke, Zheng, Hai-Lei, Dong, Shu-Peng & Ren, Ming-Xun, 2019, Molecular phylogeny of Hiptage (Malpighiaceae) reveals a new species from Southwest China, PhytoKeys 135, pp. 91-104 : 91

Hiptage incurvatum K.Tan & M.X.Ren sp. nov. Figs 2 , 3

Type.

China. Yunnan Province: Pingpo Town, Mt. Cangshan, Dali City, 25°35'N, 100°02'E, 1400 m altitude. 31 Mar 2019, K. Tan and M.X. Ren 2019033110 (holotype: HUTB!, isotypes: HUTB!, KUN!)

Diagnosis.

Similar to H. tianyangensis in ovate leaf shape, suborbicular petals; but differing from this species by sepal glands twice big as H. tianyangensis (vs. sepal gland, ~ 3 × 1 mm), the elevation ca. 400 m (vs. 1379-1724 m), the short inflorescence 1-4 cm (vs. 4-10 cm).

Description.

Woody lianas; stems 20-30 (-200) mm diam. Branches round, lenticels white or greenish, tomentose to glabrous, with white to grey hairs. Leaves opposite; stipules absent; petioles ca 0.5 cm long, round, tomentose, with white hairs, eglandular; leaf blades 6-12 × 2.5-4.5 cm, elliptic, base cuneate, margin plane, apex attenuate, both surfaces sericeous, 10-16-glandular dots abaxially near margin, lateral veins 5-8 pairs, prominent on both surfaces. Thyrses , solitary, axillary or terminal; main axis 4-10 cm long, tomentose, with white hairs; peduncles 1.5-2.5 cm long, tomentose; bracteoles inserted below the apex of peduncles, 0.3-0.5 cm long, lanceolate. Flowers with pedicels 1.5-2.5 cm long, sericeous, with white hairs; sepals 5, ca. 0.5 cm long, elliptic to oblong, margin slightly revolute, apex rounded, adaxial surface glabrescent, abaxial surface white tomentose; glands 4 (-6), 0.5-3 × 0.5-1 mm, prominent, rounded, restricted to sepals, two large, basally fused glands on the dorsal sepals, remaining glands small and free; petals white to light pink, yellow at the base, ca. 1 × 0.8 cm, suborbicular, extremely reflexed, claws ca. 1 mm long. Stamens 10, filaments white or light yellow, free or basally fused, 7-13 mm long, glabrous; anthers ca. 0.5 × 0.3 cm, ovate, pubescent, with yellow hairs; pollen sacs dehiscing longitudinally. Ovary ca. 2 mm diam.; styles 1, light pink, ca. 13 mm long, curved upwards, deflected either to the left or right side, glabrous; stigma apical. Mericarps 3, each flower developing up to three mericarps, detaching from a pyramidal torus; individual mericarps three-winged (laterally placed in the nut), wings pink with greenish base, the posterior wing ca. 3.6 × 1.3 cm, ovoid, apex round or slightly lobed, with white or brown hairs; anterior lateral wings ca. 2.3 × 0.7 cm, lanceolate, arcuate back to the middle; nut ca. 0.2 cm, round or slight ovate, glabrous; areole ca. 0.3-0.6 cm, roughly triangular. Seeds angular-globose, ca. 3-5 mm, dark yellow or brown.

Additional specimens examined (paratypes).

China. Yunnan Province: Pingpo Town, Mt. Cangshan, Dali City. 31 Mar 2019, K. Tan and M.X. Ren 2019033109 (HUTB), K. Tan and M.X. Ren 2019033108 (KUN).

Phenology.

Flowering from April to May, and fruiting in May.

Distribution and habitat.

Hiptage incurvatum is only known from two localities near Mt. Cangshan, Pingpo Town, Dali City, North Yunnan, growing on soil slopes or forest margins and river valleys, at 1400-1700 m. In China, a total of 13 species of Hiptage now have been recorded, 10 of which, including the new species, are endemic to the country ( Chen and Funston 2008; Ren 2015; Yang et al. 2018).

Etymology.

The specific epithet reflects the arcuate and curved anterior lateral wings of the three-winged samara.

Vernacular name.

Chinese: 弯翅风筝果 ( wān chì fēng zhēng gǔo). The name ‘wān chì’ means arcuate wing, 'fēng zhēng gǔo’ is the Chinese name of Hiptage .

Conservation status.

The only two known populations of Hiptage incurvatum are in Pingpo Town of Dali City, in a river valley near Mt. Cangshan. These two populations have about 50 individuals in total along the woodland margins or slopes of the valley near a road. Very limited information is known about the new species. Therefore, H. incurvatum can be treated as Near Threatened (NT, close to being at high risk of extinction in the near future under the criterion [B1ab(iii) + 2ab (iii)] according to the IUCN Red List criteria ( IUCN 2013).

Notes.

The new species can be clearly identified from three similar species ( H. benghalensis , H. multiflora , H. tianyangensis ) from the following traits. Leaf: H. incurvatum (ovate, 6-12 × 2.5-4.5 cm) is smaller than all the three species, i.e. H. tianyangensis (ovate, 7 –12× 3-5.5 cm), H. multiflora (oblong, 12-13 × 5-5.5 cm), H. benghalensis (elliptic, 9-18 × 3-7cm). Petal color: H. incurvatum (white with light pink), H. tianyangensis (white), H. multiflora (pink), H. benghalensis (white with yellow on the vexillum). Calyx glands: H. incurvatum (2 large and fused at the lower part, not decurrent to the pedicel; sometimes 2 or 4 smaller glands can be seen on other sepals), H. tianyangensis (2, small, clearly isolated, not decurrent to the pedicel), H. multiflora (1, large, not decurrent to the pedicel), H. benghalensis (1, very large, 1/2 adnate to the pedicel).

Figures

Figure 2. Hiptage incurvatum K. Tan & M. X. Ren, sp. nov. A, B habit C flowering branch D flower in frontal view E flower with petals removed in sideview F flower with petals removed in dorsal view showing two large glands on the dorsal sepals) G flowers in sideview H detached petals I young leaf in adaxial view J young samaras K mature samaras L leaf branch in adaxial view. Photos A-C by M. X. Ren, J, K by H. L. Zheng and D-I, L by K. Tan.

Figure 3. Line drawing of Hiptage incurvatum K. Tan & M. X. Ren, sp. nov. A flowering branches B flower (in sideview) C sepals showing two large glands on the dorsal sepals and small glands on the remaining sepals D samara in dorsal view, showing the curved lateral wings E samara in sideview. Drawings by Ya-Jing Zhang based on K. Tan and M. X. Ren 2019033109 (HUTB).