Ophiorrhiza pseudonapoensis L. Wu & Q. R. Liu 2023, sp. nov.

Ophiorrhiza pseudonapoensis L. Wu & Q. R. Liu, sp. nov. (Figs. 1–3) Type:— China. Yunnan: Hekou county, Nanxi town, alt. 950 m, Ẵễ (Lei Wu) 4225 (holotype, CSFI076284!; isotypes, BNU!, CSFI076278!, CSFI076285!, CSFI076286!, CSFI076287!). Diagnosis:— Ophiorrhiza pseudonapoensis is similar to O. napoensis, but the former differs from the latter in having 5–10 (vs ca. 1) mm long stipules, persistent (vs caducous) bracts, oblanceolate (vs lanceolate-linear) bracts, homostylous (vs heterostylous) flowers, and ensiform (vs narrowly triangular) calyx lobes. The new species also resembles O. macrocarpa L. Wu & Q. R. Liu (2018: 2), but it can be distinguished from the latter by its 5–10 (vs less than 1) mm long stipules, oblanceolate (vs subulate or linear subulate) and 7–20 (vs less than 5) mm long bracts, and (1.2–)1.5–2(–2.5) (vs 0.4–0.6) mm long calyx lobes. Description:— Erect or suberect herbs, 25–35 cm tall; stem glabrous, often dark purplish when dry. Leaves usually in unequal pairs; petiole shorter than 1 cm, blade drying papery, dark greenish adaxially, greenish-yellow abaxially, lanceolate, oblanceolate, or ovate-lanceolate, 7–17(–21) × 2–4 cm, base cuneate, margin entire, apex acuminate, glabrous on both surfaces; secondary veins 9–12 on each side, both sides flat, clearly visible abaxially; stipules narrowly triangular, 5–10 mm long, apex acuminate, persistent. Inflorescences congested-cymose, terminal, erect, usually many flowered; peduncles 1–4 cm long; axes 0.3–2.5 cm long, helicoid, puberulent or subglabrous; bracts oblanceolate, 7–20 mm long, apex obtuse, glabrous. Flowers homostylous on 1–2 mm long pedicels. Calyx puberulent; lobes 5, ensiform, (1.2–)1.5–2(–2.5) mm long, with one gland at each sinus; hypanthium 1.2–1.5 × 2–2.5 mm, inconspicuously 5-ribbed. Corolla pale pink or white, drying yellow-brown, salverform, glabrous outside; tube 25–28 mm long, glabrous inside except puberulent at the throat; lobes 5, subovate, 4–5 × 3.5–4 mm, dorsally smooth, rostrate at apex. Stamens 5, attached to the throat of the corolla tube; anthers linear-oblong, ca. 2.0 mm long; filaments 1.5–2.2 mm long, glabrous; stigmas 0.5 mm long, sub-capitate, shallowly bilobed, reaching a little higher than anthers. Capsules mitriform or obcordate, ca. 3 × 9 mm. Seeds many, angular. Phenology:— Flowering from October to January of next year. Etymology:— The specific epithet is derived from its morphology that is closely resembling Ophiorrhiza napoensis. Distribution and Habitat:— Ophiorrhiza pseudonapoensis is only known from southeastern Yunnan until now. All individuals observed in the wild are distributed in limestone areas and grow in humid places, such as along stream banks, or sometimes on wet cliff under dense forest cover at altitudes of 500–1500 m. Conservation status:— So far, only two Ophiorrhiza pseudonapoensis populations in Maguan and Hekou with more than 1000 mature individuals were observed during our investigations. And the population we discovered from Maguan is in the Gulinjing provincial nature reserve, where habitats are in good condition and there are no threatening factors until now. According to the type specimens, we speculate that there are more than ten populations with more than 2000 mature individuals in total from southeastern Yunnan, and the distribution area is more than 30 km 2. Thus, this species is assigned a status of Least Concern (LC) following the guidelines of IUCN (2022). Additional specimens examined (paratypes):— CHINA. Yunnan: Maguan, X.T. Cai 51898 (IBSC), Y.J. Hu GS86-2101 (IBSC), Chen & Li 86SL-343 (IBSC, YSY), 86SL-7946 (IBSC, YSY), GL86-2051 (IBSC, YSY), GL86- 7558 (IBSC, YSY), GL86-7864 (IBSC, YSY), Y.M. Shui et al. 30216 (PE), 31119 (IBSC, PE), L. Wu. 4232 (BNU, CSFI); Xichou, A.Q. Wu 7761 (KUN), 7899 (KUN), without locality, Z.L. Lin 14031304 (KUN). Notes:— Flowers of Ophiorrhiza napoensis were described by Lo (1990) as “corolla tube 2–2.2 mm long, stamens inserted at the throat of corolla tube, stylus 1.3–1.4 cm long, stigma 2.5–3 mm long, 2-lobed”, and its biology was noted as “it might be homostylous” in the protologue. Through a careful observation of floral trait correlations, Kudoh et al. (2001) indicated that O. napoensis has both long- and short-styled morphs, viz. stigmas positioned at the throat while anthers located a little above the middle of the corolla tube in the long-styled form, and opposite in the short-styled form. However, in recent work, Tao & Taylor (2011) followed the description of Lo (1990) instead of Kudoh et al. (2001) and noted that the floral biology of this species as unknown. After several field investigations in Guangxi and Yunnan, southwestern China, we support the conclusion of Kudoh et al. (2001) that the flowers of O. napoensis are heterostylous (Fig. 4, C–I), and confirm the O. pseudonapoensis is a misidentification of O. napoensis. Ophiorrhiza pseudonapoensis is also similar to O. macrocarpa based on flower form and corolla shape but differs in having longer stipules (5–10 mm) (vs less than 1 mm in O. macrocarpa), longer bracts (7–20 mm long) (vs less than 5 mm), oblanceolate bracts (vs subulate or linear subulate), and much longer calyx lobes (1.2–2.5 mm long) (vs 0.4–0.6 mm long) (Fig. 4, A–C). More detailed comparisons among the three species are listed in Table 1.Published as part of Liu, Qin, Chen, Ao-Xue, Liao, Xiao-Wen, Liu, Quan-Ru & Wu, Lei, 2023, Ophiorrhiza pseudonapoensis (Rubiaceae), a new species from Yunnan, southwestern China, pp. 228-234 in Phytotaxa 607 (4) on pages 229-233, DOI: 10.11646/phytotaxa.607.4.1, http://zenodo.org/record/824332