Aristolochia phoenixa M. Y. Xue, R. Z. Huang & Han Xu, 2025

Xue, Miao-Ya, Huang, Rui-Zhou, Yang, Hai-Jun, Lu, Chun-Yang & Xu, Han, 2025, Aristolochia phoenixa, a new species of Aristolochiaceae from Hainan Island, China, Phytotaxa 708 (1), pp. 87-94 : 88-90

Aristolochia phoenixa M. Y. Xue, R. Z. Huang & Han Xu , sp. nov.,

Figs. 1–2 .

Diagnosis: — Aristolochia phoenixa is most similar to A. ledongensis Han Xu, Y. D. Li & H. J. Yang and Isotrema sanyaense R. T. Li, X. X. Zhu & Z. W. Wang in terms of morphology. Aristolochia phoenixa is comparable to A. ledongensis in having a similar shape of the leaf blade (lanceolate or elliptic-lanceolate, entire, base shallowly cordate) and the yellow to brown villous indumentum of the pedicel, ovary and calyx, but significantly differs in the following characters: U-perianth tube consisting of the calyx, with purple stripes outside (vs. with yellow to brown stripes in A. ledongensis ), basal tube ca. 20.0–26.0 × 5.0–6.0 mm, yellow window pane and dark purplish red stripes (vs. ca. 15.0– 16.0 × 4.5–5.0 mm, yellow window pane without stripes in A. ledongensis ; ca. 22 × 5 mm, dark purplish red window pane without stripes in I. sanyaense ), dark purplish red spots in the central part of utricle (vs. without dark purplish red spots in A. ledongensis ; dark purplish red spots in the half of the U-shape lines in I. sanyaense ); upper tube yellow without spots (vs. yellow with spots in A. ledongensis ); flowering time November to December (vs. August in A. ledongensis ; October in I. sanyaense ).

Type: — CHINA. Hainan: Ledong Lizu Autonomous County, Jianfengling Tropical Rainforest National Park , Sandui village, 18°44'47.9741"N, 108°55'47.3977"E, ca. 643 m, 16 November 2024, Xue MY 2024001 (holotype CANT!, isotype IBSC!)

Description: —Woody, perennial, scandent lianas. Stem terete, up to ca. 5.0 m long; young stems densely villous with brown, becoming glabrescent; old stems leafless; bark corky and with irregular longitudinal fissures. Leaves alternate; petiole terete, 1.5–3 cm long, lamina lanceolate to elliptic-lanceolate, entire, 12.0–16.8 × 3.5–5.2 cm, leathery, adaxially flat, with sparsely found brown hairs, abaxially prominent veins, densely covered with appressed yellowish brown hairs, veins pinnate, 6–14 pairs, tertiary veins coarsely reticulate, base shallowly cordate to cordate, sinus 2.3–3.0 mm deep, acuminate at apex. Inflorescences with 1–3-flowers, axillary or cauliflorous; pedicels 1.8–2.2 cm long, with densely brown trichomes; bracteoles on the upper part of pedicel, ovate-lanceolate, ca. 0.1–0.2 × 0.1 mm, brown, apex acuminate, densely brownish villous. Flowers: calyx geniculately curved, outside white to yellowish with purple-red stripes, and densely yellowish to brownish villous; perianth tube U-shaped, ca. 2.2–2.6 cm long; utricle pendent, basal portion of tube 2–2.1 × 0.8–1 cm, shorter than the upper part, inner part of basal tube light purple, with yellow window pane and dark purplish red stripes, light yellow in the middle, central part of utricle with dark purplish red spots and lines, pubescent; upper portion of tube 2.6–3 × 0.8–1 cm, inside yellow; limb discoid, 1.0– 1.6 cm in diameter, bright yellow, petaloid, equally 3-lobed, lobes widely ovate with densely papillae, recurved, glabrous; throat dark purplish red, 5.0–6.0 mm wide, glabrous; gynostemium ca. 5 mm long, apex 3-lobed, lobes acute; anthers 6, oblong, bright yellow, ca. 2 mm long, pairwise adnate to the stigmata forming a gynostemium; ovary cylindrical, 6-angled, 6-loculed, carpels connate, ca. 8.0–10.0 mm long, ca. 2.0 mm in diameter, densely brown villous. Capsule puberulent, ca. 5 × 2.5 cm, 6-angled. Seeds not seen.

Phenology: —Flowering specimens have been collected in November. The fruiting period occurs between February and March of the following year.

Etymology: —The specific epithet “phoenixa ” is inspired by the colour and shape of the flower which resembles both a saxophone and a phoenix—a mythical bird in Chinese mythology. In the Western Han Dynasty, the renowned man of letters and musician Sima Xiangru had created a remarkable piece of music titled “The Phoenix Seeks Its Mate”, and its melody not only captures the passionate courtship between the protagonists, but also symbolizes their extraordinary ideals and the profound understanding between kindred spirits ( Watson 1993). This theme aligns particularly well with the pollination biology of flowering plants, especially suitable for the designation of this new species. The Chinese name is given as “凤凰马兜铃”.

Distribution and habitat: — Aristolochia phoenixa is currently known from Jianfengling, Hainan Island, China. It grows in evergreen broadleaved forests and near streams dominated by families such as Fagaceae , Lauraceae , Myrtaceae and Rubiaceae at elevations between 600– 650 m.

Preliminary conservation status: — Aristolochia phoenixa is a new species discovered in Jianfengling, Hainan Island, China, with fewer than five individuals found in the field. Several plant surveys have been carried out at the discovery site, but no other populations have been found. However, due to the small size of the area surveyed in the field, we assume that additional populations may be found in similar habitats in and around the region. Therefore, based on the IUCN Red List Criteria ( IUCN 2024), it is recommended that the protection status of this species is Data Deficient (DD). Due to the relatively low numbers of individuals discovered in the wild, suitable protection strategies should be developed for the protection of this new species.

Figures

FIGURE 1. Aristolochia phoenixa M. Y. Xue, R. Z. Huang & Han Xu, sp. nov. A. Habitat; B. Leaf venation; C. Inflorescence with two closed flowers; D. Flowers (front view); E. Flowers (dorsal view); F–G. Longitudinally dissected flower (showing the internal structure and dorsal view); H. Gynostemium with stigmata and adnate anthers (lateral view). Drawn by MiaoYa Xue based on MiaoYa Xue 2024001 (CANT).

FIGURE 2. Aristolochia phoenixa M. Y. Xue, R.Z.Huang & Han Xu, sp. nov. A. Mature plant in its native habitat; B–E. Leaf laminas (adaxially, abaxially view and detail with indumentum); F. Inflorescence with closed immature flowers; G. Flowers (front view) H–I. Longitudinally dissected flower (showing the inside structure and lateral view); J–K. Flowers (dorsal view and lateral view); L. Bracteoles; M–N Flowers (inside of the basal and central part of utricle); O–P. Gynostemium (lateral and top view); Q–R. ovary; S. Capsule. Photographs by MiaoYa Xue & Hai Jun Yang.