Impatiens baishaensis B. Ding & H. P. Deng, 2017

Impatiens baishaensis B. Ding & H. P. Deng , sp. nov. ( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 ).

Type:— CHINA. Sichuan Province: Hongya County, Wawu Township, Baisha River, Wawu Shan Provincial Nature Reserve , 29°26′48.17″N, 102°54′20.49″E, ca. 2250 m a.s.l., 24 September 2015, B. Ding 201509060 (holotype PE! GoogleMaps , isotypes PE! GoogleMaps , SWNTU! GoogleMaps ).

Diagnosis: Similar to I. oxyanthera in having 2-flowered racemose inflorescences and pink flowers with reddish veins, but differs from this species by having smaller flowers, abaxial midveins of lateral sepals and dorsal petal puberulent, dorsal petal spotted with purple-red, and lower sepals navicular.

Description

Herbs, annual, 30–70 cm tall, Stems erect, branched. Leaves alternate, petiolate or subsessile on upper stem; petiole 0.5–3 cm; leaf blades ovate-oblong, 3–8 × 1–3.5 cm, membranaceous, adaxially puberulent, with 2–5 stipitate glands at base, base cuneate, margin crenate, apex acuminate. Inflorescences axillary, 2-flowered, peduncle 2–8 cm long, puberulent, pedicels 0.5–2 cm long, bracteate above base, bracts persistent, lanceolate, ca. 5 mm. Flowers pink, 1–1.5 cm long; lateral sepals 2, ovate, ca. 5 × 3 mm, entire, apex acuminate, abaxial midvein puberulent. Lower sepal navicular, ca. 0.8 cm long, abruptly narrowed into an incurved spur; spur slender; mouth vertical, tip acute; dorsal petal orbicular, ca. 7 × 7 mm, purple–red spotted, base retuse, apex rostellate, abaxial midvein puberulent; lateral united petals not clawed, with fuchsia striations, ca. 1 cm long, 2-lobed; upper lateral united petals orbicular, purple-red spotted; lower lateral united petals dolabriform, auricle linear, elongate. Stamens 5, filaments linear, anther small, apex obtuse. Ovary 4–5 mm long, erect, apex acuminate, glabrous. Capsule erect, linear, 2–2.5 cm long, 5-angled.

Palynology— Pollen grains oblong in polar view, 4-colpate, P×E = (11.9–14.5) 13.2 × (25.7–28.6) 27.2 μm, broadly ellipsoid in equatorial view; sexine ornamentation reticulate, bottom of ridge with irregular granules, lumina sparsely granulated ( Fig. 3A–C View FIGURE 3 ).

Seed micromorphology— Seeds ellipsoid, 3.3 (3.1–3.5) × 1.8 (1.6–1.9) mm. Some of the seedcoat epidermal cells are elevated significantly higher and arranged in ridges ( Fig. 3D View FIGURE 3 ), bulliform cells sunken ( Fig. 3E–F View FIGURE 3 ).

Etymology— The epithet baishaensis refers to the locality of the type specimen.

Phenology— Flowering and fruiting from July to November.

Habitat and distribution— Impatiens baishaensis occurs in forest understories, along canals, shaded moist places, and roadsides at elevation 2100–2300 m. Presently, the new species is known only from Hongya and Liangshan counties, Sichuan, China.

Conservation status— Only five populations are known, with a total of about 1000 individuals; the area of occupancy is less than 10 km 2. We classify the conservation status of Impatiens baishaensis as Vulnerable (VU D2), based on current information and following the International Union for Conservation of Nature and Natural Resources guidelines ( IUCN, 2016).Although the area is under protection as a national nature reserve, habitat disturbance brought about by human activities such as grazing and trampling may have a negative impact on the species.

Paratype — CHINA. Sichuan: Meigu Dafengding National Natutre Reserve , Forest understories, along roadsides, 28°44′14.15″N, 103°14′53.61″E, ca. 2200m a.s.l., 3 July 2016, B. Ding 20160702 ( PE!) GoogleMaps .

Similar species— Impatiens baishaensis is superficially similar to I. oxyanthera in its inflorescence comprising two pink flowers with a reddish vein. However, it differs from this species by the following characters: flower much shorter: 1–1.5 cm vs. 2–2.5 cm; lateral sepals abaxial midvein puberulent vs. lateral sepals abaxial midvein smooth; dorsal petal abaxial midvein puberulent vs. dorsal petal abaxial midvein smoooth; dorsal petal purple-red spotted vs. dorsal petal purple-striped; lower sepals navicular vs. lower sepals subsaccate-funnelform.