China. Gansu: Longnan City, Yuhe Area of Giant Panda National Park, altitude ca. 1200 m, 4 April 2020, Zengfu Bai & Xuelin Chen 2020001 (holotype: NWTC!; isotype: NNBG!).

Illicium gansuense is similar to I. ternstroemioides and I. arborescens in overall form, leaf characters, red flowers, location, and population density. Illicium gansuense can be distinguished from I. ternstroemioides and I. arborescens based on leaf-blades size (7–12 × 1.8–3.5 cm in I. gansuense vs. 7–13 × 2–5 cm in I. ternstroemioides vs. 6–12 × 2–4.5 cm in I. arborescens), tepal number and pubescence (10–17 tepals with ciliate margins vs. 10–14 tepals with glabrous margins vs. 14–21 tepals with glabrous margins), number of carpels (10–13 vs. 12–14 vs. 12–16), number and size of the stamens (23–27, 2–3 mm long vs. 22–30, 1.8–3.4 mm long vs. 39–41, 2–3 mm long), and ovary length (1–1.5 mm long vs. 1.3–2.5 mm long vs. 1–1.8 mm long). (Table 1).

Trees 4–12 m tall, whole plant with an aniseed aroma. Trunk 22.5 cm diam. at chest height, outer bark grayish-brown, with irregular longitudinal cracks; canopy tower or conical and branches are dense and spread horizontally; twigs pubescent, perules ca. 3 × 2 mm, ovoid, yellowish-brown, caducous, margins finely ciliate. Leaves clearly spirally-alternate to pseudoverticillate (clustered in sets of 2–5 at the apex of twigs); petioles 8–12 mm long, 1–2 mm diam.; blades 7–12 × 1.8–3.5 cm, oblanceolate, coriaceous, translucent oil spots visible against the light, adaxially dark to medium green, glossy, abaxially light green, base cuneate, margin glabrous, apex acuminate; midvein adaxially slightly impressed, abaxially prominently round, lateral veins pairs 6–9, inconspicuous. Inflorescences 1-flowered, but flowers sometimes clustered in groups of 2–6 at the apex of branches, axillary, pedunculate; peduncle 8–14 mm long, 2 mm diam., brown, bracteoles 2–4 × 2–3 mm, ovate. Flowers 12–18 mm diam., bisexual, androgynous scented, anthesis diurnal; floral buds 5–10 × 3–6 mm, ovoid, brown; pedicels 5–12 mm long, 2 mm diam., brown; tepals 10–17, in 2–3 whorls, outer whorl with 5–7 tepals, 6–8 × 5–7 mm, ovate, sepaloid, yellowish-green, base round, margin red, ciliate, apex acuminate or obtuse, inner whorls with 8–10 tepals, 8–12 × 4–8 mm, widely ovate to widely obovate to widely elliptic, petaloid, fleshy, red, base broadly cuneate, margin ciliate, apex acuminate; stamens 23–27, in 2–3 whorls, 1.3–3.5 mm long, filament 0.3–1.5 mm long, stout, widely obovoid to widely ellipsoid, pink, connective truncate to emarginate, pink, anther 1–2 × 0.6–1 mm, introrsely rimose, pollen grains trisyncolpate, blackish-brown in vivo; carpels 10–14, 3–5.5 × 1.6–2 mm, ovaries 1–1.5 mm long, stigmatic crest 1.3–1.8 mm long, slightly longer than the ovary, subulate. Follicetum 12–16 × 4–7 mm; peduncle 1–1.5 cm long; follicles 10–13, 15–25 × 5–8 mm, 2–4 mm thick, woody, dark brown, apex aristate due to the persistent and hardened stigmatic crest, 3–6 mm long, slightly curved at apex. Seeds 4.5–6 × 4–5 mm, 1.5–2.5 mm thick, ovoid, testa smooth, brown.

Currently, only one population of I. gansuense has been identified in Yuhe Town, Longnan City, southern Gansu Province. This area is characterized by a northern subtropical subhumid climate and a mountainous terrain containing high peaks and steep slopes. Specimens of I. gansuense were found growing in a deciduous broadleaf forest at an elevation of 1200 m. The dominant species of this forest community include Trachycarpus fortunei (Hook.) H.Wendl. (Arecaceae), Cinnamomum septentrionale Hand.-Mazz. (Lauraceae), Lindera aggregata (Sims) Kosterm. (Lauraceae), and Deyeuxia effusiflora Rendle (Poaceae). (Fig. 1)

Figure 1. 

Distribution of Illicium gansuense.

Flowering from March to April, fruiting from May to November.

There is only one known location, and fewer than three individuals of I. gansuense were found during our fieldwork in the Yuhe area of Giant Panda National Park in 2020 and 2022. However, investigations of the natural distribution of this species are insufficient. According to the IUCN Red List criteria (2019), this new species is better assessed as Data Deficient (DD; criteria B1ab(i–v) + 2ab(i–v)).

Figure 2. 

Illicium gansuense Z.F.Bai & Xue L.Chen A flowering branch B adaxial and abaxial leaf surface C flower D tepals E removal of tepals showing gynoecium and stamens F, G stamens, dorsal and ventral views H carpel I fruiting branch J, K fruits L seed. (Drawn by Jianlu Bai based on type specimen).

The specific epithet ‘gansuense’ refers to a province in eastern China. 甘肃八角 (gān sù bā jiǎo) is suggested as a suitable Chinese name for it.

Figure 3. 

Illicium gansuense Z.F.Bai & Xue L.Chen A habitat B, C flowering branch D bark.

Illicium gansuense is similar to I. ternstroemioides and I. arborescens in overall form, that are all trees, leaf characteristics, flower color, location, and population density. However, as noted above, the three species can be distinguished according to both morphological features and distribution. Specifically, in relation to I. ternstroemioides and I. arborescens, I. gansuense is characterized by smaller leaf blades, tepals with ciliate margins (rather than glabrous), fewer carpels, and smaller ovaries. Additionally, I. gansuense blooms from March to April and I. arborescens blooms from January to April. (Table 1).

Figure 4. 

Illicium gansuense Z.F.Bai & Xue L. Chen A flower at front view B flower at side view C the largest tepals D all parts of flower E stamen F follicle G fruit at front view H fruit at side view I seed. Photographed by Zengfu Bai.