Peliosanthes orthocoronata H. Z. Feng 2024, sp. nov.

Peliosanthes orthocoronata H.Z. Feng, sp. nov. (Fig. 1) Diagnosis: —Morphologically most similar to Peliosanthes griffithii Baker (1879: 506) (Fig. 2), but lacks horizontal stolons, the perianth lobes are revolute and entire, and the staminal corona distally slightly narrowing. Type: — CHINA. Yunnan province: Wenshan Zhuang and Miao Autonomous Prefecture, Hekou Yao Autonomous County, Ma-duo-yi-nanshan (Ḷ 多依南Ɯ), in elev. 545 m, 20 April 2024, Feng 20240421 (holotype: SYS!). Description: —Herbs perennial, rhizomatous, short, simple or with a few branches, 1–2.5 cm long, partially covered with scarious or papyraceous remnants of cataphylls, bearing few, dull light yellowish-brown wiry roots. Roots, few, poorly branched, ca. 1.7 mm in diameter, rigid, densely covered with root hairs. Leaves usually basal, cataphylls up to 2.5 cm long, up to 4.5 mm wide, chartaceous, lanceolate, light green, soon becoming dry, sheathing. Foliage leaves ascending, simple, stiff. Petiole adaxially flattened, 4.5–8.5 cm long, 0.5–1.4 mm in diameter. Leaf blade entire, elliptic, 6–8 × 2–4 cm, dark green; base narrowly cuneate, entire, glabrous, uniformly green and glossy on both sides; longitudinal veins 5 (including midvein), parallel; transversal veinlets numerous, visible, sub-perpendicular to longitudinal veins. Inflorescence a lax raceme (i.e., flowers solitary in axils of primary bracts), erect to ascending, up to ca 10 cm long. Peduncle erect, 5–7.5 cm long, ca 1–1.5 mm in diameter, longitudinally ribbed, violet, bearing 4 or 5 sterile bracts; sterile bracts 8–9.5 mm long, base 2–2.5 mm wide, scarious when mature, indistinctly unicostate, navicular, triangular, green. Rachis straight, up to 3.5 cm long, longitudinally ribbed, violet, bearing up to 16 flowers. Flowersubtending bracts 6–8 mm long, 1.5 mm wide, scarious when mature, navicular, lanceolate, caudate at apex, violet. Flowers sparsely arranged, actinomorphic, bisexual, facing horizontally to slightly nodding, generally dark violet to brownish violet. Pedicel 4 mm long, 0.8–1 mm in diameter, articulated with ovary. Bracteole absent. Perianth rotate, homochlamydeous, 5–6 mm in diameter when fully opened; lobes 6, arranged apparently in two similar whorls with imbricate-alternate aestivation (in bud), at anthesis outer lobes slightly overlapping inner lobes; lobes subequal, ca. 2.5 mm long, ca. 1.6 mm wide at base, narrowly ovate-triangular, revolute, horizontally spreading, dark violet. Stamens 6; filaments united forming fleshy corona-like structure (so-called corona); corona 1.5–1.8 mm high, 2.5–3.0 mm in diameter, erect (or columnar), apically with six prominent broadly triangular lobes, 0.2–0.7 mm long, erect or incurved, dark violet and sometimes greenish especially along tepal bases; orifice of corona 1.5–1.7 mm in diameter; anthers sessile, attached to the inner surface of corona lobes just below orifice, dorsifixed, introrse, ca. 0.6 mm long, cylindrical to ovate, longitudinally dehiscent. Ovary semi-inferior, broadly obconical, ca. 1.5 mm high, 1.5–2 mm wide in upper part, 3-locular, each locule bearing 4 ovules; style ca. 1.2 mm high, ca. 1 mm wide at base, columnar with three prominent furrows along borders between carpels; stigmas 3, carinal. Seeds unknown. Etymology: —The specific epithet refers to the shape of corona; orthocorona is composed of “ortho+corona”, “ortho-” means upright. Habitat and phenology: —Primary or secondary broad-leaved evergreen forests on rocky limestone, at elevations 450–700 m a.s.l.; terrestrial or lithophytic clustering herb on shady rocky slopes. Flowering in April–May. Distribution and conservation: —Endemic to lowland limestone areas of Southern Yunnan province. In observed locations locally common. Estimated IUCN red list status: ‘Least Concern’ (LC). Rare, but locally abundant. Note: — Peliosanthes orthocoronata is closely related to P. griffithii, sharing a short, erect staminal corona and a columnar style. P. griffithii was described based on a single collection, Griffith 5840 (holotype: K000099365, photo!), from East Himalaya, Darjeeling, India. While P. orthocoronata resembles P. griffithii, it clearly differs in several key aspects: P. griffithii has a long, slender stoloniform rhizome that can extend up to 32 cm or longer (Tanaka 2018), and its perigone segments are inwardly curled and distally minutely denticulate-erose (Averyanov et al. 2016a; 2016b, Tanaka 2018) (vs. revolute and entire). Additionally, in P. griffithii the corona distally slightly recurved, but in P. orthocoronata distally slightly narrowing. Peliosanthes orthocoronata is also similar to P. serrulata Rodriguez (1934a: 96) (lectotype, designated by Tanaka 2019, A. Chevalier 31824, P00214607 photo!) (Fig. 3), described from Cambodia, but the latter has distinctly serrulate leaf margins (vs. entire), a dense inflorescence (vs. sparse), and lanceolate perigone segments that are 2–3 mm long and 1 mm wide (vs. 2.5 mm long, ca. 1.6 mm wide at base, narrowly ovate-triangular). Additionally, the segments are spreading (vs. reflexed), the anthers extend beyond the staminal corona (vs. being enclosed), and the stigma is conical (vs. columnar) (Rodriguez 1934b: 670, figs. 9–12). Averyanov et al. (2016b) suggested that P. serrulata and P. griffithii are very similar in morphology, with minimal differences, and therefore could be merged. However, in Tanaka (2019), P. serrulata was still not combined with the latter. In addition, P. orthocoronata is also similar to P. sinica F.T.Wang & Tang (1978: 253) (Figs. 4 & 5), described from Southern Yunnan, as both have erect corona. However, the latter has a long stolon that the annual nodes spaced at intervals of 7–13.5 cm (based on holotype), with a conical stigma (vs. columnar). Peliosanthes orthocoronata is also somewhat similar to P. elegans Averyanov, N. Tanaka & Vuong (2016: 28), but the difference is that the former has purple flowers (vs. whitish), perianth lobes revolute (vs. margin revolute), and the corona erect (vs. corona conical).